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Title: Preliminary Report on Gowganda Mining Division District of Nipissing Ontario
Author: Collins, W. H.
Language: English
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MINING DIVISION DISTRICT OF NIPISSING ONTARIO ***
Transcriber’s Note
When italics were used in the original book, the corresponding text has
been surrounded by _underscores_.
Some corrections have been made to the printed text. These are listed in
a second transcriber’s note at the end of the text.
CANADA
DEPARTMENT OF MINES
GEOLOGICAL SURVEY BRANCH
HON. W. TEMPLEMAN, MINISTER; A. P. LOW, LL.D., DEPUTY MINISTER;
R. W. BROCK, DIRECTOR.
PRELIMINARY REPORT
ON
GOWGANDA MINING DIVISION
DISTRICT OF NIPISSING
ONTARIO
BY
W. H. COLLINS
[Illustration: Colophon]
OTTAWA
PRINTED BY C. H. PARMELEE, PRINTER TO THE KING’S MOST
EXCELLENT MAJESTY
1909
No. 1075
13739-1
CONTENTS
PAGE.
I. Introduction.
1. Location and area 5
2. Statement of work 5
3. History of development 6
II. Summary and Conclusions 8
III. General Character of District 10
1. Means of access 10
2. Topography 11
3. Drainage 14
4. Flora and fauna 15
IV. General Geology 16
1. Outline of Geological history 16
2. Table of formations 18
3. Keewatin 18
General features 18
Obushkong area 18
Duncan Lake area 20
Pigeon lake area 21
Unfinished areas 22
4. Laurentian 23
General features 23
Relations to other formations 24
5. Huronian 25
General features 25
Basal conglomerate 26
Greywacke slate and quartzite 27
Upper conglomerate 27
Arkose 28
Structural features and disturbances 28
Relations to other formations 29
Origin and correlation 31
6. Post-Huronian eruptives 32
Quartz diabase 32
Character of intrusion and distribution
relative to older systems 32
Macroscopic character 33
Microscopic character 34
Local description 36
Age 37
Olivine diabase 38
7. Pleistocene 38
V. Economic Geology 40
1. Silver 40
Distribution 40
Surface indications 40
Structure of veins 41
Composition of veins 41
Local description 42
Future possibilities 44
2. Copper 45
3. Iron ores 45
Hematite 45
Magnetite 46
4. Asbestos 46
Distribution 46
Origin 47
ILLUSTRATIONS.
1. Frontispiece—View at Foot of Duncan Lake 5
2. Diagram illustrating the structure of large hills 12
3. Diagram illustrating geological relationships 16
4. View looking north from middle of Duncan Lake, 550 ft.
hill in distance 20
5. West Branch Montreal River, near Mosher Lake 22
6. Fifth portage on West Branch of Montreal River, showing
Huronian slate 30
7. Inclined Huronian Beds, Duncan Lake 32
R. W. BROCK, Esq.,
Director Geological Survey Branch,
Department of Mines.
SIR,—I beg to submit the following preliminary report upon work done in
the Gowganda Mining Division during the field season of 1908.
I have the honour to be, sir,
Your obedient servant,
W. H. COLLINS.
CHICAGO, March 8, 1909.
[Illustration: Fig. 1. View at foot of Duncan Lake.]
PRELIMINARY REPORT
ON
GOWGANDA MINING DIVISION
DISTRICT OF NIPISSING, ONTARIO
BY
W. H. COLLINS.
--------------
INTRODUCTION.
LOCATION AND AREA.
The portion of the Montreal River region with which the present report
deals lies in the extreme western part of the District of Nipissing, in
the neighbourhood of N. Lat. 47·45, and about 85 miles north of the town
of Sudbury. It includes an area of 350 square miles, most of which lies
between the two large branches of the Montreal river, which empties into
Lake Timiskaming on the west side.
STATEMENT OF WORK.
The Algoma-Nipissing boundary line was run in 1897 by Alexander Niven,
O.L.S. These surveys, with representations of some of the larger lakes,
had been compiled by the Geological Survey of Canada on a scale of 16
miles to one inch;[1] and on a scale of eight miles by the Crown Lands
Department of Ontario. With these as a guide and summary of the existing
geographical knowledge it was decided to make a micrometer and prismatic
compass survey of both branches.
During the past season a prismatic compass and micrometer survey was
made of both branches of the Montreal river and all navigable waters
adjoining them. This work was done by Messrs. T. Firth, J. R. Marshall
and A. B. Moffatt. Most of the small ponds lying some distance from a
canoe route were located by rapid chain and compass methods, and in a
few instances west of Duncan lake by a compass triangulation from
hilltops; the larger ones have been measured by pacing or chaining, the
smaller ones sketched. Some of the more prominent hills were located by
triangulation, and their heights ascertained by aneroid determinations.
The water levels were obtained in the same way, but cannot as yet be
referred to sea-level.
The geological work was performed by the writer, assisted by Mr. Firth.
Besides a thorough examination of all the surveyed routes, a systematic
examination of the intervening country was carried out as closely as the
time and varied requirements of the area would permit. As this was the
first season spent in the district and a continuation of the work is
anticipated, the present results are offered as incomplete and subject
to revision.
HISTORY OF DEVELOPMENT.
Since the discovery of silver cobalt ores at Cobalt in 1903, exploration
has shown the adjacent country to be locally enriched by mineral veins
of the same character and genesis. At the close of 1907 an area 65 miles
long in a north and south direction, and about 45 miles wide, extending
from Lake Timiskaming and the Ontario-Quebec boundary westward, was
known to include at least ten mineralized districts besides the
principal one at Cobalt, of which the most recently found lie near the
Montreal river. It has also become known gradually that these deposits
are closely connected with the post-Huronian quartz diabase of the
region. This diabase was known to extend for a very considerable
distance farther west, leading to the inference that more discoveries
were to be expected in that direction. The spring of 1908 saw interest
centred upon the Montreal River finds, and early in the season active
exploration had commenced. The Montreal river, up to that time, had not
been regarded with special favour, the diabase being considered of no
economic importance, but with the new conceptions gained by exploitation
of the silver-cobalt district, this formation in the west began to
attract attention. At the beginning of the field work, early in July, a
considerable number of prospecting parties were on the ground, as far
west as Duncan and Pigeon lakes. During July and August this movement,
encouraged by the succession of mineral discoveries that were being made
near Bloom and Everett lakes, increased steadily, in spite of the
scarcity of available topographical and geological information dealing
with the region.
Early in August discoveries of native silver were made almost
simultaneously by Messrs. Mann and associates, and by Messrs. Crawford
and Dobie on the west side of Gowganda lake, but were not made public
until the first week in September when the claims were recorded at Elk
Lake and specimens were exhibited. Twenty-four hours later the leading
canoes of an inrushing body of prospectors had reached the new field,
and within two weeks most of the promising country between Gowganda and
Elkhorn lakes and northward had been staked, regardless of the mineral
discoveries necessary to validate the claims. Since then numerous
discoveries have been made, and the news of a new silver field, until
recently confined to the Montreal River and Cobalt districts, has spread
widely. As a consequence, a mid-winter rush is now in progress, and
hundreds of prospectors, regardless of deep snow and severe cold, are
entering the country. Much inadvisable staking will be done, no doubt,
before spring, but the disappearance of the snow and reopening of river
navigation will certainly be followed by an increased rush of
prospectors.
SUMMARY AND CONCLUSIONS.
The results obtained from the field work indicate that the Montreal
River district does not differ essentially from the Cobalt or other
neighbouring districts. The surface has the same rugged monotony of the
pre-Cambrian peneplain, relieved somewhat by ridges of Huronian, which
stand from 300 to 550 feet above the general level. The country is well
watered, and offers exceptional facilities for canoe travel. Pleistocene
deposits are thin, and nearly everywhere the rock formations are well
exposed.
A basement complex underlies the entire region, either appearing at the
surface or hidden beneath areas of Huronian sediments. This basement
consists largely of Laurentian biotite and hornblende gneisses, with
patches of vertically foliated, Keewatin schists caught up in the
former; the intervening contacts forming indefinite zones, in which
intrusive action is manifested. In this report, for convenience, this
complex will be referred to as the Archæan. The Archæan possessed a
peneplanated surface, not greatly different from the present one, which
is well preserved where overlain by erosion remnants of Huronian
sedimentary rocks, but which at other points has been further denuded.
The Lower Huronian rocks are of clastic nature, consisting in ascending
order, of conglomerate, greywacke, slate and quartzite, which pass
conformably into an upper conglomerate; while a granite-like, arkose
member is believed from its similarity to rocks of the same character in
the Cobalt area, to be possibly of later, Middle Huronian age. They are
remarkably well preserved, and show only slight indication of
disturbance. A later intrusion of quartz diabase has developed a system
of dikes in the Archæan and large tongue-shaped areas in the Huronian
believed to represent sills of several hundred feet thickness, lying in
the bedding planes of the Huronian sediments. The diabase magma has been
notably differentiated, giving rise to forms ranging from gabbroid to
syenitic in composition, and to younger aplite dikes. With the diabase
is associated a group of veins containing an association of cobalt and
silver ore identical with that of Cobalt and vicinity. The veins cut
both diabase and aplite as well as the Huronian, and are therefore
younger, but probably not much younger than the aplite, since it
contains some of the minerals found in them. The distribution of the
veins so far as known is confined to the larger diabase areas, the dikes
and smaller bodies being undifferentiated and unmineralized; but the
Huronian adjacent to the diabase also contains veins, somewhat more
siliceous, yet evidently of the same age as the others. Alteration and
impregnation of the country rock has taken place to an unknown, but,
presumably, limited extent. Some of the veins are remarkably rich, and
many of them occupy persistent, well defined fissures. The cause of
these fissures is not yet known, but they appear to be too large and
continuous to have resulted from contraction alone.
GENERAL CHARACTER OF DISTRICT.
MEANS OF ACCESS.
In 1908 the most used route to the Montreal River district started from
Latchford, a station on the Timiskaming and Northern Ontario railway, 93
miles north of North Bay. From this village, situated on the Montreal
river, a line of small steamers made daily trips up the river for 56
miles to Elk lake. This up-river terminus was then a rapidly growing
village. In the spring of 1907 it consisted of a single shack and a
cluster of prospectors’ tents; when seen in October, 1908, it had a
population of over 200 people and all the conveniences of a village of
that size, including a post office with regular mail service, a mining
recorder’s office, lately removed from Latchford, general stores,
hotels, etc.
From this point, which forms the headquarters and point of departure for
Montreal River prospecting parties, a variety of routes lead westward.
The Montreal river may be ascended to the Forks, where its two branches
unite, but the stream is rapid, and, especially in high water, difficult
of ascent, besides offering a very indirect route to the most frequented
districts. The Bloom Lake route, a map of which accompanies the Report
of the Bureau of Mines, Ontario, 1907, was, during 1908, very commonly
used. This route, 9 miles in length and consisting of a chain of small
lakes and portages, leads, from a point on the main river 11 miles above
Elk Lake, directly west to the East branch. From the East branch a
multiplicity of courses are open. Both East and West branches are easily
navigable, being for the most part lake-like and sluggish, broken by
occasional swift river-like stretches in which rapids occur. Good
portages exist at all these places so that travel either up or down
stream presents no difficulty. Numerous good canoe routes connect the
two branches and Duncan and Pigeon lakes, and allow of easy access to
the country in the west.
But since the writer left the field the great influx of prospectors has
caused marked improvements in the connexion of the area, especially the
Gowganda district, with outside railway points. A sleigh road has been
opened from Charlton on the Timiskaming and Northern Ontario railway to
Elk Lake, and thence about 32 miles south-westward to the east shore of
Gowganda lake. It is understood that heavy grades make travel somewhat
arduous, but the trip from Elk Lake is made easily in a day.
On February 4, a sleigh road about 65 miles long was completed between
Gowganda and Sellwood, the present terminus of the northern extension
from Sudbury of the Canadian Northern railway. A regular stage route now
connects Sellwood, Phoenix, Burwash lake, Elkhorn lake, and Gowganda.
However, neither the road to Elk Lake nor that to Sellwood are yet
suitable for summer use, so that with the coming of spring, canoe travel
must be again resorted to. It is also reported that preliminary surveys
for the extension of the railway to Gowganda are in progress. Meanwhile
a business centre is springing up on the east side of Gowganda lake. A
sawmill was put in operation on February 3, but has since been stopped
owing to its location within a government timber reservation. A town
plot has been laid out at the foot of the lake and lots are now
purchasable from the Ontario Department of Lands, Forests and Mines.
Buildings are being erected as rapidly as the supply of material
permits. A branch of the Royal Bank of Canada has been opened, and the
Canadian Bank of Commerce and others propose to be on the ground within
a short time. Postal connexions have been established via Sellwood, and
as soon as possible a mining recorder’s office is to be opened. So
swiftly are events transpiring that before the present report takes
printed form, this paragraph will be in need of revision. However, only
the developments of a permanent nature and of essential interest to
prospective visitors to that region have been given. For the 1909 field
season Gowganda will probably be the headquarters for prospecting
parties in the neighbourhood of the East and West branches and Wapus
creek.
TOPOGRAPHY.
Attention is given here rather to the details than the general aspect of
the country. It exhibits the usual monotonous succession of low rocky
hills and lake-containing depressions, the even horizon seen from the
summit of any large hill, being only rarely notched by a prominence of
unusual height. In the spring of 1908 virtually the whole area was
forested, but during September the extreme dryness of the country and
the unusually large number of camping parties combined to cause bush
fires over much of the country between the East and West branches. The
vegetable loam has been removed from extensive tracts leaving the rock
formations exposed, but the charred tree trunks have fallen so as to
cover the burnt districts with a ‘slash,’ which greatly impedes
cross-country travel, so that what has been gained in one respect is
more than counterbalanced in another. Especially is this the case in the
country west of Gowganda and Obushkong lakes, and near the Forks.
The general surface may be characterized as of comparatively low-relief,
the hills not often rising over 200 feet, but here and there over the
country are conspicuous elevations, visible at long distances, which
form useful landmarks and from whose summits comprehensive birds-eye
impressions of the surrounding country are possible. Structurally they
appear to be, in a few cases, resistant knobs of Keewatin, which project
well above the general peneplain level, but more commonly they are
tilted ridges of Huronian. A characteristic representative of the latter
type forms a long ridge beginning a mile and a quarter north-east of
Duncan lake and extending thence for several miles in a north-easterly
direction. The south-east side of this ridge slopes gently at an angle
corresponding with the dip of the beds, but the north-west face is an
abrupt cliff dropping almost perpendicularly for about 400 feet to a
flat sandy plain which extends westward and northward for several miles,
beyond which are other monadnock-like knobs. The accompanying diagram is
intended to represent the structure in vertical cross-section.
[Illustration: Fig. 2.—Vertical section across Huron Ridge, North of
Duncan Lake.]
Another ridge of similar character, standing 550 feet above the level of
Duncan lake, is visible from the ridge just described and from points on
Duncan and Otto lakes, and adjoining country. Its position as indicated
on the map is about four miles north of the large island in the middle
of Duncan lake, a view of it from this point being shown in fig. 4. In
this case the east face is perpendicular. A prominent hill of the same
kind is visible from Obushkong lake, lying a short distance to the
north-west of that body. Just west of Mosher lake as represented in fig.
5, two round hills of about equal size rise 300 feet above the water
level. The more southerly of the two is of Keewatin, while that to the
north is composed wholly of diabase, Huronian lying around the base of
each. Bold, but less individualized elevations are common in the
neighbourhood of Kenisheong lake, and other localities. All these hills
are markedly rocky and free from soil.
Less conspicuous than these great masses are certain minor, but
persistent features which are directly referable to geological
conditions. Within Huronian areas there is a distinct tendency toward
the development of a system of parallel ridges similar in structure and
mode of origin to the hill at the north-east of Duncan lake. This
feature is developed with special regularity in the southern part of the
wedge between Duncan lake and the West branch, where a succession of
north and south ridges alternate with strips of swampy ground. The
western faces of the ridge are bare and cliff-like, while the eastern
slopes are gentle, well soil-covered and forested.
The post-Huronian diabase is an equally potent topographical factor. Its
surface is one of marked irregularity, but the peculiarly distinctive
features occur at its contacts with the Huronian. These contacts appear
to be zones of low erosive resistance, and are commonly coincident with
ravines, walled on one side by diabase, on the other by Huronian. Small
lakes may occur at intervals along them as, for example, between Firth
lake and the West branch. This erosion feature is well shown by the
configuration of Gowganda lake, where diabase bodies are unusually
abundant; both of the long arms to the north-west lie in trough-like
depressions marking the edges of the eastern diabase mass. The same
tendency in an incipient condition is observable on the east side of the
large peninsula where a series of three land-locked bays extend along
the contact between the eastern diabase mass and the Huronian. Near the
middle of Duncan lake, a diabase-Huronian contact which crosses the lake
diagonally is marked by two deep bays, one extending to the north, the
other southward. While this tendency is an evident one it is not to be
understood as invariable; the large island in Duncan lake between the
two above-mentioned bays is sufficient to indicate that contacts may lie
in high ground, yet even here there are minor features indicating the
contact zone to be structurally weak.
Another less explicable topographic peculiarity becomes apparent only
upon scrutiny of the drainage system. A brief consideration of the map
shows that both East and West branches follow peculiar zig-zag courses
running north for a short distance, then turning abruptly east, this
feature recurring repeatedly. In some instances the east-west portion of
both branches lies in the same line. In the case of Zigzag lake and
adjacent portions of the West branch this feature is repeated with an
almost conventional regularity, which precludes attributing it to chance
causes. Many of the smaller lakes—Foot lake, for instance—exhibit the
same character on a small scale. This abnormality has been commented
upon by investigators in the country to the east, the courses there,
however, being N.E.-S.W. and N.W.-S.E. Regional faulting is suggested in
explanation. The canyon-like east and west walls of Zigzag lake suggest
such conditions, but a discussion of the matter must be deferred until
further data can be collected.
DRAINAGE.
All the drainage water escapes by way of the Montreal river, whose two
chief tributaries are the East and West branches, the latter being
considerably the larger. The East branch is without feeders of important
size, but the West branch receives a large creek, the Wapus, from the
south, and a considerable volume of water enters through Duncan lake.
In common with most rivers traversing the pre-Cambrian region, this
water system is marked by a volume of dormant water enormously greater
than that being transported at any given moment. With few exceptions the
many small tributary brooks rise in lakes or groups of lakes
surprisingly large in size, compared with the volume of the out-flowing
streams; Otto and Lehmann lakes are drained by a rather sluggish rivulet
8 feet wide and 6ʺ deep, although their combined area is about two
square miles. The larger streams themselves are only successions of
irregular lake expansions which empty from one to another by short,
river-like portions containing rapids and falls. The descent is
therefore accomplished by a succession of abrupt steps rather than an
evenly graded slope. This juvenile condition is directly ascribable to
the geological character of the country; soil deposits are insignificant
in quantity, leaving exposed a resistant and uneven rock floor in which
the streams are unable to carve channels for themselves. Failing to do
so they select the readiest egress by filling up impervious rock basins
and spilling over at the lowest points into lower ones. In consequence
of the scantiness of soils and frequency of natural settling basins, the
waters of the whole system are free from suspended matter, and hence
lack of an effective graving instrument. Exceptions to this general
character occur in the extensive sand plain to the north and west of
Duncan lake, where the several small creeks that traverse it are of
ordinary fluvial form and gradation, and the waters of which transport
large quantities of sand to Duncan lake.
FLORA AND FAUNA.
Where not recently burned the country is fairly well forested, the
density and character of growth being dependent upon soil and drainage.
The best timber is in low ground and near watercourses where conditions
for growth are most favourable and the probability of fire least. Recent
fires have done much damage around Nest, Obushkong and Gowganda lakes.
Probably the best timber lies near Duncan lake. Trees do not grow very
large as a rule and are not especially good for making lumber, but
provide an abundant supply of materials for pulpwood, railway ties, fuel
and for mine use.
White pine is the most valuable species, but although individuals attain
thicknesses of 20ʺ to 40ʺ they are too scarce to render this timber
worth the search. Good red pine is more abundant. Jack pine is a very
common tree, especially in sandy districts, _e.g._, north-west of Duncan
lake; but is small and worthless. The common and most widely distributed
species are spruce, balsam, cedar, poplar, white and yellow birch.
Tamarack is not abundant. Clumps of small red maples were seen to the
south-west of Pigeon lake.
The East and West branches are not well suited for carrying logs as
there are extensive lake expansions without current on each and the
rapids are shallow. Excellent water-power is obtainable at the 40 foot
fall on the West branch above Fort Matachewan.
Wild animals are not abundant, and will probably become less so as the
country is occupied by prospecting and mining camps. Moose were
plentiful in 1908 and some black bears were seen. As a source of food
the abundance of pickerel and pike is of much greater importance. Brook
trout do not occur in the Montreal River waters, but are caught farther
to the west and north.
GENERAL GEOLOGY.
OUTLINE OF GEOLOGICAL HISTORY.
Though the geology of the region presents considerable complexity of
detail, the general historical facts are distinct and go to show that
the whole complex of formations and systems is capable of separation
into four major divisions widely different from one another. The mutual
relationships of these divisions, a knowledge of which is essential to a
thorough comprehension of the geology, are succinctly expressed by the
accompanying diagram.
[Illustration: Fig. 3.—Diagram illustrating geological relationships of
Montreal River district.]
The oldest division, the Keewatin, comprises a complex association of
metamorphosed rocks, principally eruptive, characterized by
well-developed, secondary schistosity and prevalently dark colours. They
dip at angles approaching 90° and range in texture from soft, fissile,
chorite schists to fine-grained gneisses or altered diabases. In the
Montreal River district the Keewatin areas are not entirely visible,
being overlain by other rocks, but they are thought to represent the
bottoms of trough-like folds, produced by the upward intrusion of
igneous matter which now constitutes the Laurentian. The latter forms
the second division, its origin being apparent from the foregoing
statement. It is wholly igneous, consisting of granite and allied
coarsely crystalline rocks essentially pale-coloured owing to their
richness in quartz and feldspars. Gneissic structure has been developed
in varying degrees, so that all gradations between granite and gneisses
exist; but it never attains the perfection found in the Keewatin. Near
their contacts with the Keewatin, the gneisses are apt to contain dark
bands and ribbons of the latter so highly crystalline as to conceal
their identity.
Wherever visible the surface of the Keewatin and Laurentian presents an
irregular, deeply worn appearance, the result of extremely protracted
exposure to erosive agencies. To the best of geological knowledge the
same conditions hold where they lie buried under the Huronian,
indicating that a great period of denudation separates the latter from
the Archæan. The combined Keewatin and Laurentian, or Archæan system, is
therefore to be conceived as forming at all points in the district an
ancient denuded foundation or floor upon which rests the much younger
Huronian system.
This third division is, in the Montreal River district, wholly
sedimentary and easily distinguished from the other rocks by its bedded
structure and clastic nature. As it is the only sedimentary system
represented, its members are not easily confused with any other,
especially as their original structure is not obscured by metamorphic
alteration. Locally this is not strictly true; in the vicinity of
diabase intrusions they have been hardened and shattered so as to
simulate the Keewatin, but the zones of alteration are narrow and
readily identified by their gradation into adjacent areas of less
altered types. At present the Huronian forms a discontinuous rock mantle
over the Archæan, formerly more complete, but now worn through in places
so as to expose portions of the crystalline basement.
The fourth division includes all eruptives known to be younger than the
Huronian. Owing to the discontinuity of the latter it is not always easy
to decide what rocks should be included in this group, for in some cases
rather fresh-looking eruptives occur in the Keewatin which probably
would also intrude the Huronian were it present; lacking the necessary
information their chronological position can be only loosely fixed. By
far the most extensive and important of the post-Huronian eruptives is
the diabase with which the silver deposits are associated. This
penetrates both Archæan and Huronian, but is ordinarily distinguishable
by its unusual freshness, dark colour, and crystalline appearance. In
certain cases, to be described subsequently, it may be confused with
certain other diabases. Magmatic differentiative processes have evolved
diabase types of very dissimilar appearance and mineralogical
composition, of which a pink aplite occurring in dike form is the most
extreme. Olivine diabase dikes are also present in the region, but in
far less abundance.
Of little importance are the sands and gravels of glacial origin which
lie thinly in the depressions and lower lands of the present glaciated
surface.
TABLE OF FORMATIONS.
The geological events may be briefly enumerated in ascending order as
follows:—
Deposits of glacial débris and weathering products of present surface.
Erosive period with glaciation.
Diabase intrusions.
Huronian sedimentation.
Erosion period.
Laurentian intrusion.
Keewatin.
KEEWATIN.
_General Features._
This system is considered as a complex assemblage of metamorphosed
igneous rocks whose common and marked characteristics are pronounced
alteration and deformation, accomplished in pre-Huronian times. A
limited amount of sedimentary material, such as the iron ore formation,
is also represented. These old diabases, porphyries and related types
are much altered and have developed a more or less uniform schistosity
through the secondary development of micaceous minerals, but in other
respects the complex shows extreme inconstancy and variety from point to
point. For this reason the various localities are separately described.
By inspection of the map three fairly well defined areas are
distinguishable, in addition to which are portions of several others.
_Obushkong area._
Much of the country between Obushkong and Firth lakes is underlain by
Keewatin. On the east, south and west sides, these rocks disappear
beneath the Huronian or are interrupted by masses of diabase, but on the
north they merge into Laurentian gneiss, the contact with which is
ill-defined. Although some of them retain much of their original massive
character, well defined schistosity is the dominant feature. The schists
stand vertically or at angles little less than 90° and trend in a
general east and west direction. A series of compass observations made
at points over the whole area show the strike to vary from N. 65° E. to
S. 75° E.
One of the most abundant rock types is a stratiform, finely speckled
hornblende gneiss or schist, the black hornblende cleavage faces giving
it a glistening appearance on newly broken surfaces. It is quite fresh,
perfectly crystalline and usually eminently fissile, but sometimes
grades into a nearly massive dioritic form of undoubted igneous nature.
Extensive exposures occur around Gould lake where the gneiss is
traversed by numerous stringers of quartz, rusty in colour from the
oxidation of pyrite. It is also well exposed near McLaughlin and
McIntosh lakes and to the east and south-east of Foot lake. A fine
grained chlorite schist of dull greenish black colour is common in this
and all the other areas in the district. To the north-east of Serpentine
lake it appears as a sheared phase of a weathered diabase, but it has
also been derived from porphyry, exposures being seen between Foot and
Obushkong lakes, where feldspar phenocrysts appear on weathered surfaces
of the schist as pale, oblong spots. What is probably iron formation was
observed at points 25 chains south of Gould lake, and 10 chains south of
a little pond just east of Serpentine lake. Both outcrops consist of
banded, grey quartzite interlaminated with chlorite schist, but
magnetite-bearing bands were not found. Occasionally, narrow bands of
pale grey, felsitic schists may be seen among the more common darker
rocks. From evidence obtained at various points, these appear to have
resulted from the decomposition and shearing of granite porphyry dikes
probably connected with the Laurentian, and which penetrated the
Keewatin during the time of Laurentian intrusion. Serpentine was
observed between Foot lake and Obushkong at 20 chains from the latter.
The surface is covered by a loose network of fine seams of asbestos
which weather white and render the rock somewhat conspicuous. Its
recognition is further simplified by the dull green, amorphous
appearance of fresh surfaces, the slight translucence of thin edges and
the glistening green seams of asbestos which traverse it abundantly. The
same rock is more extensively exposed on the south-west of Serpentine
lake and on Firth lake half a mile north of the portage leading to the
former, also at less than a quarter of a mile south of this portage. It
is associated with and derived from a dark green massive rock to which
the name wehrlite is applicable, and a more detailed description of
which appears later.
_Duncan Lake Area._
A Keewatin area of considerable extent lies between Duncan lake and the
West branch in the vicinity of L’Africain and Beaverhouse lakes. Unlike
the Obushkong area, the prevalent strike of the schists is nearly north
and south, the greatest divergence noted being 25° W. In the former case
Laurentian lies to the north, while in the present one it occurs on the
east; in both cases the schistosity coincides approximately with the
direction of the line of contact. On account of the swampy character of
the country just west of the river and the scarcity of outcrops, this
area was not completely explored, but wherever examined the Keewatin, as
in the Obushkong area, consists predominantly of hornblende and chlorite
schists, greenstone and decomposed diabase; but serpentine was not
found. A nearly black diabase containing small grains of pyrite was
observed 20 chains south-east of the southerly extending bay on Duncan
lake, and outcrops of the same material were traced for about half a
mile northward. Probably the same type was encountered just north of
Beaverhouse lake and at some other points. Its unfoliated condition and
fresher appearance than the adjacent rocks lead to the opinion that it
is really post-Keewatin and intrusive, but the absence of younger rocks
with which to correlate it, renders its exact age indeterminable. This
rock exhibits enough resemblance to fractured contact edges of the
post-Huronian diabase to make their distinction in the field rather
difficult. At half a mile east of the south end of L’Africain lake is
diabase which from lack of sufficient data has been mapped as Keewatin,
although it may be identical with the post-Huronian variety. L’Africain
lake lies in glistening hornblende gneiss with which are associated
ribbons of a coarser hornblende gneiss belonging to the Laurentian of
the area farther east. Greenstone and chlorite schists are the principal
rocks around Beaverhouse lake. Associated with them and to the
northward, are dikes of light coloured, granite porphyry, usually only a
few feet wide, in some of which the original massive structure remains,
while others show various gradations toward a felsitic, sericite-bearing
schist. The isolated patch of Keewatin indicated on the map as occurring
about half a mile east of the wide portion of Duncan lake, is a well
foliated green schist in which oval white spots represent squeezed
feldspar phenocrysts.
[Illustration: Fig. 4. View looking north from middle of Duncan Lake,
550ʹ hill in distance.]
_Pigeon Lake Area._
West of Pigeon lake and the Montreal river, much of the country examined
is underlain by Keewatin. Schistosity is less developed than in either
of the preceding areas. The rocks are chiefly diabases and porphyry much
decomposed and locally squeezed. Diabase occurs on both sides of Pigeon
lake near its central islanded part and along the bay which extends
south to Brush lake. An original diabase structure is sufficiently well
preserved to show lath-like feldspars in hand specimens, but frequently
the rock is altered to a chloritic mass. Around the bay extending toward
Brush lake, this old diabase forms a rude wall intersected by a
reticulating system of fractures filled with calcite, the resultant
structure simulating that of a breccia. Shear zones seen on the east
shore exhibit a pseudo-conglomeratic structure, the more resistant
pieces of diabase having been partially rounded by the shearing movement
and embedded in a matrix of finely pulverized rock matter. The same
diabase apparently occurs all along the Montreal river where it follows
the Algoma-Nipissing line. About half a mile above Pigeon lake it forms
a 90 foot cliff on the west side of the river, near the top of which is
a fresher looking, unfoliated eruptive. The form of this body was not
ascertained, but microscopic examination of the specimen taken,
determines it to be a hornblende lamprophyre, so probably it is a dike
or thin sheet. The rock is fine-grained, dark green in colour and
characterized by stout prisms of hornblende about one-quarter of an inch
long, embedded in a finer, microcrystalline ground mass. Under the
microscope it appears much decomposed. This rock was also observed near
mile post 67 of the Algoma-Nipissing boundary, near the east end of the
63 chain portage leading to Breese lake and at other points, in all
cases the exposures being of small extent.
In the last mentioned locality the predominant rock is an altered
porphyry of ash grey colour. Around Porphyry lake it occurs in a fairly
massive, easily recognizable condition, the feldspars showing as square
white spots one-quarter of an inch in diameter in a grey, ground mass.
On Breese lake it has been squeezed to a felsite schist, striking N. 20°
W. In small amounts it is associated with post-Huronian diabase on the
hills lying near the Montreal river and just south of the 63 chain
portage.
The 300 foot hill south-west of Mosher lake is composed of a fine
Keewatin greenstone whose surface is curiously weathered so as to
suggest a spheroidal structure. It is marked off into round areas a foot
or more in diameter by a sinuous network of weathered-out grooves. The
main body of the rock is ordinary fine-grained greenstone, but the
enclosing grooves have been formed in porphyritic zones about an inch in
width. Among other types of less abundant distribution is an actinolite
rock seen by the unassisted eye to consist of a felty mass of acicular
crystals of actinolite, sometimes half an inch long. This rock was
observed 12 chains east of the islanded part of Pigeon lake; also at
points west of Montreal river below Pigeon lake.
_Unfinished Areas._
The Keewatin formation occupies the space between Near lake and the West
branch, only part of which has been mapped. The rocks of this area are
well foliated, standing as usual, vertically, and striking about N. 60°
E. The exposures on the east shore of Near lake are entirely of fissile,
chlorite schist, abundantly traversed by small barren quartz veins.
Farther east the chlorite schist gives place to glistening, stratiform
(laminated) hornblende gneiss with which are associated bands of a
coarser hornblende gneiss, evidently the equivalent of granite. In one
locality the stratiform rock contains subangular fragments of the
coarser variety, quartz and a greyish eruptive rock, the resultant
structure resembling that of a metamorphosed conglomerate or breccia. As
some of the brecciated fragments occur near by in continuous bands
within the stratiform gneiss, the clastic structure is to be ascribed to
deformative movement instead of original sedimentation. A number of
fine-grained quartz diabase dikes occur in the immediate vicinity.
A considerable portion of the east shore of Kenisheong lake consists of
high, bare Keewatin hills, composed largely of chloritic schists,
vertically inclined and striking east and west. Secondary calcite is
richly disseminated, causing free effervescence when the rock is treated
with acid. Pyrite is also abundant, sometimes segregated to form a lean
ore, and at several points weathered superficially to limonite,
colouring the cliffs dull red. Much-altered diabase like that on Pigeon
lake is also present in subordinate amount.
[Illustration: Fig. 5. West Branch Montreal River, near Mosher Lake.]
Keewatin rocks also occur just east of Gowganda lake. A single brief
visit was paid for the purpose of observing the iron formation which
appears at this place, and further mention of which is made on a
subsequent page.
LAURENTIAN.
_General Features._
Practically all the Laurentian lies in a continuous area, east of the
West branch and extending beyond the limits of the map sheet. A smaller
body occurs just west of Pigeon lake. The foliation in the Laurentian is
less distinct than in the Keewatin and much less perfect. Its component
rocks are mainly granite and allied plutonic types which pass by easy
gradations into well-defined gneisses. Two principal granites are
distinguishable; one containing black mica as its chief coloured
constituent, the other hornblende. Both exhibit local variations in
composition and crystalline texture, but are always pale grey rocks of
ordinary granitic appearance.
The hornblende granite is a medium grained, fresh looking rock of
speckled appearance, owing to the black hornblende crystals which lie
scattered through the main mass of light grey feldspar and quartz. It is
of uniform aspect, local variations of colour and texture being
insignificant. As revealed under the microscope by a single thin
section, it is an ordinary hornblende granite verging towards a syenite.
Common green hornblende of idiomorphic prismatic habit, and usually
twinned parallel to 100, is the principal ferromagnesian mineral. It is
quite fresh, hence a few flakes of chlorite in the section were taken to
represent an original small content of biotite; an acid oligoclase and
orthoclase are the most abundant constituents; quartz is subordinate.
Apatite, zircon and iron ore, probably magnetite, are accessory.
Hornblende granite is the commonest Laurentian rock in the neighbourhood
of L’Africain and Sedge lakes, where it is in contact with the Keewatin.
It also occurs on the East branch just below Obushkong lake. The area
west of Pigeon lake seems to be composed wholly of this rock, outliers
of which extend to Brush lake, and the islands and east shore of Pigeon
lake. Here, however, it is distinctly syenitic, quartz being subordinate
or absent. A distinctly porphyritic structure is apparent on Pigeon
lake; the feldspars being well crystallized and lying in a finer
grained, holocrystalline ground mass.
Biotite granite and gneiss are most prevalent in the northern and
eastern portions of the area. No microscopic examination of these rocks
has been made by the writer, consequently, little can be said regarding
their composition. They are of much the same texture as the hornblende
type, but show a somewhat higher degree of gneissification. Biotite is a
fairly abundant constituent, but is more or less altered to chlorite.
Sometimes, as may be seen on the East branch, two miles below Obushkong
lake, chloritized mica forms enclosing films about the large feldspar
grains, developing a slight ‘augen’ structure. Stockwork-like quartz
veins are frequent, particularly on the West branch between Near and
Sedge lakes and at the south end of Kenisheong lake. At the latter point
the biotite gneiss is well foliated and steeply tilted. A body of deep
red, biotite granite of undetermined extent and relationship was
observed on the east side of Kenisheong lake. Pegmatite dikes almost
certainly occur in this region, although not actually observed. Near
Crotch lake the granite is locally of unusually coarse texture, although
not truly pegmatitic.
Although the two granites described appear to be the essential
constituents of the Laurentian they usually contain a variable
proportion of other material, some of which at least is not really
Laurentian. Over the entire area, but more noticeably in the vicinity of
contacts with the Keewatin, they include narrow ribbons or lenses of a
glistening stratiform hornblende gneiss, closely resembling the gneiss
of this sort described under the Keewatin system. In some cases these
bands are portions of the Keewatin caught up by the Laurentian material
at the time of its intrusion and highly metamorphosed by it. Excellent
examples of this may be seen on the East branch at the foot of the
marshy stretch two miles below Obushkong lake. These inclusions are
mapped as Laurentian, being an almost constant feature, and for map
purposes inseparable from it. They are to be distinguished—a difficult
matter—from other dark inclusions believed to be drawn out, basic
segregations of Laurentian magmas; the latter are commonly less sharply
defined.
Like the other formations of the region, the Laurentian is cut by
diabase dikes of post-Huronian age which, owing to their dark colour,
are conspicuous among the lighter granite rocks. In the neighbourhood of
Zigzag lake they are abundant, and are usually from twenty to sixty feet
or more in width, the smaller of which are not large enough to map.
The relationships of the Laurentian to the other systems of the region
are expressed by the contacts with them. Between Obushkong and Firth
lakes and toward L’Africain lake it is largely in contact with Keewatin.
This contact is a vaguely defined zone rather than a line, the
formations being separated by the intermediate strip containing mingled
portions of both. Proceeding across this strip from the Laurentian to
the Keewatin, the gneisses of the former become charged with ribbons of
highly crystalline schist, already described. Near the Keewatin edge
these increase in quantity and sometimes appear as tongue-like
protrusions of that system. This condition exists along the east of
L’Africain lake; on the shores of the lake the formation is dominantly
Keewatin, but the stratiform hornblende gneiss is traversed along the
strike by thin bands of Laurentian hornblende gneiss. A few chains
eastward the gneiss bands are wider, and, at a distance of 10 chains,
hornblende granite is continuous.
Where terminated by diabase the contact is definite and not marked by
notable alteration on either side. Contacts with the Huronian are
equally sharp and unconformable, in every case the Laurentian
disappearing beneath the sedimentary formation; at the south end of
Kenisheong lake the Huronian has been trenched to a depth sufficient to
expose the underlying gneissic floor near the water’s edge.
HURONIAN.
_General Features._
Much of the area mapped, especially the north-western portion, is
composed of Huronian rocks. Originally they must have been much more
extensive, probably continuous, but erosion has removed them partially
or entirely, leaving irregular remnants distributed over the Archæan.
The top of the series is gone; consequently complete vertical sections
cannot be found. In other respects they are little changed and preserve
almost perfectly their bedding and clastic structure. Even their
positions assumed at the time of deposition have changed little for the
present strata seldom dip more steeply than 30°. They are overlain only
by unconsolidated Pleistocene materials.
_Basal Conglomerate._
The basal member of this system is a conglomerate, the areal exposure of
which is inconsiderable for the whole region or for any part, but
erosional sculpturing has brought it to light at many points. Both top
and bottom and probably all intermediate portions are visible, but a
complete section from which to determine the thickness could not be
found. The greatest continuous vertical section observed, in a hill
lying one mile south of the 550 foot hill north-west of Duncan lake, is
about 200 feet, but neither upper nor lower terminations were seen. In
the neighbouring Cobalt district an estimated thickness of 500 feet has
been assigned.
From a study of the pebbles contained, this conglomerate appears to be
composed largely, or entirely, of Archæan materials, the majority of
which are rock types occurring in situ at many places in the district.
Both the hornblende and biotite granite and their gneissic phases are
abundant. Pegmatite pebbles are sometimes found, but more usually that
rock is represented by fragments of feldspar. Pieces of glistening
stratiform hornblende gneiss and similar stratiform mica gneiss or
schist, greenstone, fine-grained porphyroids and sheared basic rocks
represent the Keewatin. Vein quartz is also present, sometimes
mineralized. In addition to these some pebbles were observed which
closely resembled slate, and one which is undoubtedly conglomeratic. A
thin section of this pebble exhibits distinct clastic structure, and the
assembled fragments are heterogeneous, so far as distinguishable,
including an actinolite rock resembling that found in the Keewatin near
Pigeon lake, and a quartzitic type composed of a colourless,
microcrystalline mosaic. The cement has been altered largely to
chlorite, but small grains of quartz are discernible in it. It would
seem, therefore, that sedimentary deposits antedate the basal
conglomerate and supply a portion of its materials; most of these,
however, are recognizable as igneous members of the Archæan, such as
occur in the vicinity.
The pebbles of the conglomerate exhibit remarkable variety in form, size
and abundance, as well as composition. Normally they are well rounded
and owe their form evidently to water action. But along with these are
others which are angular or sub-angular. The exposure near the north end
of Shallow lake shows all these forms, the materials also being quite
diverse. Ordinarily the pebbles range in size between 2ʺ and 3ʺ
diameter, frequently more, and are abundant; but, at points on Duncan
lake, on Wapus creek and the West branch, the conglomerate nature is
indicated only by occasional well-rounded pebbles, embedded in greywacke
cement at intervals of several feet or even yards. These isolated
pebbles are often 6ʺ or more in diameter, and in striking contrast with
the uniformly fine grain of the matrix. Sometimes the enclosed bodies
attain the dimensions of boulders; on an island in Duncan lake, 2-1/2
miles from the foot, a granite boulder nearly 5 feet in diameter was
observed, the associated materials being of very much smaller size.
The cementing material also presents some variety. Usually it ranges
from coarse grit to greywacke. The coarser material is less abundant
than cement of a finer type; near the foot of Pigeon lake, also at the
south end of Kenisheong lake the conglomerate is quite porous, the
interstices between the pebbles being incompletely filled. In the latter
instance these spaces are occupied by hematite. In other cases; a good
example of which occurs on the east side of Pigeon lake, half a mile
from its north end, the cementing substance is a fine black shale. On
the whole there appears to be little relationship between the texture of
enclosing and enclosed matter.
_Greywacke Slate and Quartzite._
By the disappearance of pebbles the basal conglomerate changes into a
greywacke or a shale according as the cement is one or the other.
Frequently this transition is marked by an alternation of lenticular
beds of conglomerate with the greywacke, probably indicating varying
conditions of depth or current in the water in which they were
deposited. With the greywacke and shale is associated an impure
quartzite or arkose, the whole forming a thick series whose members are
not sharply separable one from another and do not occupy definite
relative positions. For the well laminated finer grained beds the term
slate is in general use, although a secondary cleavage by which this
kind of rock is distinguished from shale does not exist. Nearly all the
prominent hills in the north-western part of the area are composed of
this series.
_Upper Conglomerate._
The greywacke-slate-quartzite series passes conformably upward into a
conglomerate differing little from that at the base. Indeed, where
conglomerate outcrops are small and isolated a distinction between the
two cannot be made with certainty.
_Arkose._
In addition to the above there is an arkose forming at least two well
defined areas, whose relations with the rest of the Huronian are in some
doubt. This rock is of distinctive appearance, resembling at first
glance an ordinary granite, but on closer inspection it is seen to
consist of clastic materials such as would result from the
disintegration of a granite. Occasional conglomerate streaks in which
pebbles of quartz and greenstone are recognizable, demonstrate its
bedded character, but ordinarily it is massive looking. Part of the
large island in the middle of Duncan lake and the shore to the south are
of this formation. It is much more widespread on Obushkong and Gowganda
lakes, the bedding being unusually well shown on the large island in the
latter body of water.
From its apparent relationship in either of these localities it might be
taken to be a member of the Lower Huronian series just described, and
equivalent to the basal conglomerate. In the Obushkong area it is
probably underlain by Laurentian, for it lies nearly horizontally, and
Laurentian is known to occur a short distance east of the lake. In the
neighbourhood of Lake Timiskaming it is said to grade imperceptibly into
granite, and is believed to be derived from the latter by detrition in
situ. Arkose, apparently identical with that under consideration, occurs
in the Cobalt district, and is thought to lie unconformably with the
greywacke, and for this reason is classified as Middle Huronian. In
these pages it is given no definite position in the formational
succession, and as there is no field evidence of its Middle Huronian
position, is not differentiated from the lower series.
_Structural Features and Disturbances._
The Huronian has been subjected to no very severe disturbance, judging
by its present condition and attitude. Frequently the strata lie almost
horizontally, as for instance at the south end of Firth lake, and in the
vicinity of Lake Lehmann, but over the most of the region they rest at
inclinations as high as 30°, this attitude remaining constant over
extensive areas, and developing a characteristic topographical feature.
From Pigeon lake eastward the dip is uniformly to the east at angles
ranging between 15 and 30 degrees and the beds overlap one another after
the fashion of slates on a roof, the resultant topographical expression
of which is a succession of north and south ridges with gentle eastern
slopes, while the western sides form escarpments. This condition appears
constant over all the Huronian east of a line midway between Pigeon and
Duncan lakes. To the extreme north-west, however, a westerly dip was
observed; the strata forming the 550 foot hill west of Duncan lake are
also either horizontal or dip gently to the west. A confident statement
cannot be made until further work has been performed, but the condition
just outlined suggests a large anticlinal structure whose arch lies a
little west of Duncan lake. However, there seems reason to believe that
the structure is more complicated than would result from simple arching
and erosion. If the present overlapping system represents the original
succession of strata a total thickness of over two miles would be
necessary, and there would be not two but several conglomerate horizons,
which is improbable. A satisfactory solution is hindered by the general
fact that planes of possible dislocation occur in low ground and are
obscured by swamp or water, but it seems evident that tilting was
accompanied by lateral or vertical displacements.
Certain abrupt disturbances of the general uniform attitude suggest
differential movements. Along the West branch below Wapus creek the dip
and strike of the shale and greywacke are constant, until where the
river’s course changes to due east. Along the shores of this stretch the
rocks are mostly hidden by swamp, but where they do outcrop they are
standing vertically or dipping steeply to the south, and the strike
corresponds with the course of the stream; that is, their positions are
at right angles to those farther south. Disturbances of this sort are
known, due to the contiguity of igneous intrusions, but at this point no
such intrusive is known. It will also be seen from the map that exactly
in the same line the East branch makes a similar abrupt change in
course. Whether a line of low relief is continuous across the interval
between the two streams at this point is not easily determined; however,
as a possible explanation of the conditions stated, faulting along this
line is suggested. A similar abrupt change from conditions of
approximate horizontality to a dip S. 60 W., < 80° and strike of S. 30°
E. was noted on the west side of Firth lake.
_Relations to other Formations._
The intrusion of the quartz diabase into the Huronian was gently
accomplished at most points, and the beds of the latter, both above and
below the intrusives, are inclined only a few degrees more steeply than
in localities where no diabase can be found. Evidence of intrusion,
however, is common, and at some points the Huronian next to the diabase
has suffered local but intense physical change. Near the middle of the
east shore of Firth lake a rocky islet only a few square yards in extent
consists of coarse diabase and conglomerate in intimate contact, little
tongues of the former being protruded into the sedimentary rock and
peripherally chilled. Most remarkable, however, is the change in
condition of the conglomerate; a few chains away on the main shore it is
of ordinary character, but on the islet the pebbles lie within a fairly
well foliated schist, standing vertically and striking about east and
west. An identical condition exists at the south end of a little pond
lying 40 chains west of Mosher lake. The vertical foliation of the
conglomerate suggests the neighbouring diabase intrusion to have been by
vertical ascension rather than lateral spread, so that these points may
represent portions of vents through which the diabase magma ascended,
and for that reason are more affected than where sills have been quietly
injected.
Ordinarily these contacts occur in low ground, usually ravines, the
bottoms of which are soil filled and consequently unfavourable for
geological observation, but at some points on Duncan lake the contacts
are exposed and the Huronian is seen to be much fractured across a zone
extending many feet from the diabase. In addition to the fracturing the
greywacke is hardened and the bedding planes rendered obscure, the total
effect being to weaken its power of resistance to erosion.
In the neighbourhood of these contacts the Huronian is well supplied
with quartz veins whose ‘comb’ structure and chalcopyrite-galena
mineralization identify them with similar veins in the diabase. Also the
sediments exhibit certain mineralogical alterations referable to action
of the diabase. West of Gowganda, on the West branch below Duncan lake
and at other places the greywacke for a width of about two feet from the
diabase has been hardened, bleached a light grey colour and filled with
circular black spots 1/16ʺ in diameter. Microscopic examination shows
the main portion to consist of a mosaic of small quartz, orthoclase and
acid plagioclase grains, through which are distributed patches of
chlorite. This spotted phase of the greywacke evidently represents an
early stage in the development of adinole, a characteristic contact
product of shales, intruded by basic rock.
[Illustration: Fig. 6. Fifth Portage on the West Branch of Montreal
River, showing Huronian Slate.]
The relations of the Huronian to the Archæan, exhibited in larger as
well as minor features, indicate that the surface of the latter had been
carved into a condition not greatly unlike the present topography,
before its submergence and sedimentation in Huronian times. Some of the
hills of this ancient land have been uncovered by the removal of their
sedimentary blanket, leaving vestiges of the latter around their bases
as in the case of the hills south-west of Mosher lake. There the dip of
the sedimentary beds is much less than the slope of the hills, so that
the latter must project up through them as cores. In the bay on the east
side of Pigeon lake Huronian shales dipping with an angle of about 15°
abut against the side of an Archæan hill composed of hornblende granite
and green schist. At almost any part of the region where both Huronian
and Archæan occur together, similar evidence is available concerning the
unevenness of the pre-Huronian land surface. The amount of topographical
relief cannot be estimated with any degree of accuracy, for tops of the
Keewatin hills now exposed have probably been removed by post-Huronian
erosion, the lowest depressions are still filled by Huronian and the
whole may have been disarranged by post-Archæan faulting. However, near
Mosher lake there was a minimum relief of 300 feet.
This old pre-Huronian surface is not often accessible for study, the
contacts being vertical or hidden by soils and vegetation. At one point,
however, at the end of the portion of Wapus creek shown on the map,
exceptionally favourable circumstances were encountered. Here glaciation
has developed a rounded knoll of mixed Keewatin and Laurentian rocks
upon which are tightly fastened a few scale-like vestiges of Huronian
conglomerate. A few square feet of the original Archæan surface exposed
by chiseling away the Huronian, was found to be much more highly
polished than the immediately adjoining, recently glaciated surface
which had been exposed to the atmosphere. The protected material seemed
to be of about the same freshness as that exposed. This pre-Huronian
surface is evidently a water-worn one, or the result of Huronian
glaciation, but no characteristic markings were observed upon it.
_Origin and Correlation._
From the foregoing consideration of the Huronian as seen in the Montreal
River region it will be plain that it is composed at all points of
clastic sedimentary deposits. Fossils have never been found, so the
correlation of these rocks in various areas is based upon their
lithological similarities and continuity. Upon these grounds the
Huronian of the present district is considered to be equivalent to the
same formations in the Cobalt, Larder Lake, and other neighbouring
districts, known as the Lower Huronian. The succession and physical
character of the different formations are essentially identical. It is
not necessary to review the facts upon which the decision to so place
these formations is based, the evidence being the harmonious results of
years of investigation by capable geologists. Accepting their
conclusion, and calling the main sedimentary series of the Montreal
River district, Lower Huronian, it is of interest to note indication of
sedimentary materials still older. The conglomerate pebble found in the
basal conglomerate on Pigeon lake must have originated by the
destruction of a pre-Huronian conglomerate formation.
It has also been stated that ground for differentiating between a Lower
and Middle Huronian in this area has not been obtained, although the
similarity of the arkose to a formation in the Cobalt district believed
to belong to the Middle Huronian suggests it to be of the same age. It
is, therefore, thought desirable to apply to the whole the term
Huronian. No clearness or additional truth would be gained by making a
distinction between Lower and Middle divisions in this district, and so
far as the economic exploitation of the district is concerned the arkose
seems to be as much a part of the Lower Huronian as the conglomerate or
greywacke.
POST-HURONIAN ERUPTIVES.
There are two kinds of diabase known in the district, one of which
greatly exceeds the other in extent and economic importance. This
disparity is tacitly recognized by the common use of the generic term
diabase for the important quartz diabase, the other member of the family
being ignored or unknown.
_Quartz Diabase._
[Illustration: Fig. 7. Inclined Huronian Beds, Duncan Lake.]
_Character of contacts and distribution._—Bodies of this rock are not
restricted to any one formation or locality; but, as may be seen by
reference to the map, occur with various dimensions over the whole area,
with the exception of the country lying north-west of Duncan lake. It
may be noted that virtually all the large areas are enclosed by
Huronian, the bodies within the Archæan being numerous but small. It is
not proposed to apply this distinction generally, but in the Montreal
River region it seems to be more than an expression of the law of
probability. In the Archæan practically all of the observed diabase
bodies are dikes, in approximately vertical positions, seldom 100 feet
in width and of undetermined length. A knowledge of all those in the
Huronian could not be obtained, but in some cases they are sills, whose
greater exposed dimensions are parallel to the bedding planes of the
enclosing sedimentaries.
_Macroscopic character._—It is fortunate for the easy recognition of the
diabase that it is more or less continuously exposed, and that there are
not many other igneous rocks of similar character in its proximity, for
it presents a variety of types such that a representative collection of
hand specimens presents surprisingly great petrological differences.
During the process of solidification, magmatic differentiation evolved
from the cooling material a group of forms of different mineralogical
composition and physical appearance, the end members of which are very
unlike.
The common type is a dark green massive diabase, ranging in texture from
one in which the individual minerals are barely distinguishable to
others containing amphibole crystals an inch in length. The combination
of black amphibole—an alteration product of augite—and grey or
flesh-coloured plagioclase give the surface of ordinary textured phases
a colouration of sufficient determinative value. In a large diabase body
the coarseness is equal to that of ordinary granite, and the diabasic
structure is not readily perceptible. At the edge of the large dikes and
throughout the smaller ones the rock is black in colour and much finer
grained on account of its more rapid solidification.
In the dikes the mineralogical composition is tolerably constant, and
specimens selected from different points show no notable difference
except that they are usually less decomposed than the coarse grained
varieties. Within the larger bodies, where cooling may be considered to
have been slower, a series of rock types differing from one another in
mineral composition, and consequently in physical appearance, are
associated. At many localities these differentiated varieties are
intimately intermingled, so that within an area of a few square yards
almost the whole series may be found. Conditions of this sort were first
and best observed in the Lett properties on Wapus creek, where the
extensive stripping and trenching greatly facilitated geological study.
A suite of specimens was obtained which exhibit an unbroken gradation
from ordinary gabbro to the fine grained pink rock known as aplite. With
a decreasing pyroxene content and increasing abundance of feldspar the
rock grades from a dark green diabase at the basic end through a reddish
phase into a type which, in the field, might be termed a syenite, being
of granitic texture, red colour, and without visible quartz. These
phases are cut by aplite dikes which at first glance do not very closely
resemble them, but their comparison has shown that they too include a
group whose coarsest and most basic form does not differ greatly from
the syenitic type of the diabase series. From a pale flesh-coloured rock
of fine granitic texture in which a little dark mineral is visible, the
successive phases of the aplite graduate toward a dike material of light
pink colour and saccharine texture almost devoid of ferromagnesian
constituents.
_Microscopic character._—The consanguinity of diabase and aplite is
further established by microscopic study. It was intended to make a
somewhat complete comparative study; but, at the outset, the materials,
although fresh looking in the hand specimens, were found to be much
decomposed, sometimes so completely that the original composition could
not be satisfactorily inferred, and an outline must suffice therefore
until fresher material is secured.
The common gabbro type consists essentially of long prisms of
plagioclase embedded in light reddish augite. This ophitic structure,
upon which the distinction between diabase and gabbro depends, is well
developed, but does not show in hand specimens, so that for field use
the distinction is impracticable; ordinarily the term gabbro is applied
to the coarse grained, and diabase to the medium and finer grained
varieties. The plagioclase of the coarse grained specimens could not be
identified, being entirely altered to a coarse saussurite in which the
epidote was aggregated into large grains. The augite is almost equally
changed to strongly pleochroic hornblende possessing green and blue
green pleochroic tints. This hornblende is not a fibrous variety but
forms compact individuals, hence in the specimens studied it could not
be certain that some of it was not primary. In some cases it is further
altered to chlorite. Reaction between plagioclase and pyroxene seems to
have taken place, for chlorite occurs among the plagioclase
decomposition products as well as those of the pyroxene. Next to these,
ilmenite is the most abundant constituent, occurring as irregular masses
largely altered to leucoxene in which the original ‘gridiron’ structure
is distinct. Quartz is present in subordinate amounts usually in
micrographic intergrowth with the plagioclase. Small, well defined
hexagonal rods of apatite, titanite crystals, and rare zircons are also
present. The structure and mineral constitution render the term
quartz-diabase appropriate. Finer grained specimens secured from dikes
were found to be much fresher than the coarser types and yielded more
satisfactory thin sections; the ophitic structure is more pronounced,
but the mineral composition is the same. The plagioclase laths of one
section were determined optically to be an intermediate labradorite.
Small flakes of biotite partially altered to chlorite occur accessorily.
The aplite is also so much weathered that doubt sometimes exists as to
its original composition. Thin sections consist very largely of
plagioclase and quartz, coloured constituents being small in quantity.
The plagioclase is twinned according to albite, pericline, and carlsbad
laws, and in one case a baveno twin was observed; optically it behaves
as almost pure albite and is decomposed to sericite instead of epidote.
A poikilitic arrangement is more or less distinct; the feldspar is also
micrographically intergrown with quartz. No orthoclase could be
identified in any of the specimens. Quartz does not appear to be much
more abundant than in the diabase. The only recognizable ferro-magnesian
mineral is a strongly pleochroic reddish brown biotite, which occurs
sparingly in small ragged flakes, partly altered to chlorite. Leucoxene
representing ilmenite is surprisingly abundant considering the scarcity
of iron bearing silicates. Apatite is an abundant accessory mineral,
forming small prisms, while zircon crystals are rare. The rock in the
specimens examined is remarkably rich in calcite, which in amount ranks
next to the plagioclase.
Comparison of sections from specimens intermediate between the aplite
and the ordinary diabase brings out some features of the differentiating
process. The governing changes are in the proportion of pyroxene, and in
the composition of the plagioclase. A specimen somewhat paler in colour
than the typical diabase was found to contain considerably less augite
and more abundant plagioclase, the other constituents remaining fairly
constant. The plagioclase was an acid andesine of the composition (Ab 65
An 35). A still lighter coloured type possessed oligoclase (Ab 72 An 28)
and a small amount of blue green hornblende, representing the wholly
altered pyroxene. Orthoclase could not be found in any of the sections,
so that none of these rocks can be properly called syenite or granite.
_Local description._—Diabase is most abundantly exposed in the area
between Gowganda lake and the portage route connecting Firth and Elkhorn
lakes, where it forms three parallel tongues of approximately equal
dimensions. Coarse grained types prevail in which the differentiation of
acid phases is pronounced. Aplite dikes up to 10 feet in width, fairly
coarse grained and sometimes tolerably rich in dark constituents, are
abundant. The rugged surface of this part of the country is largely due
to the presence of the diabase, the peculiar arrangement of which has
produced a constant system of north and south ridges. The contacts with
the Huronian occupy the bottoms of gullies, with the main body of
diabase forming high ground. This highly relieved and consequently well
exposed surface has greatly facilitated the exploitation of this area,
as indeed is the case for the whole district. Terminally each of the
three bodies tapers out or forks, but these details were not closely
mapped. In the case of the most easterly one the portions reaching the
east side of Firth lake are darker and more decomposed than the ordinary
diabase, and during the field operations were considered of other
character. Laboratory study of the specimens shows them, however, to be
basic diabase in which hornblende has completely replaced the pyroxene.
In consequence of this misconception the connexions of the exposures on
Firth lake were not well worked out, but they almost certainly lie as
shown in the map and may form a continuous connexion with the large
diabase body farther north. The two areas north-east of Firth lake
present much the same appearance as those of the Gowganda district.
The most extensive body is that which coincides in direction with Duncan
lake, resembling a great hook, the shank of which is traceable for
twelve miles, the crooked end lying about midway between the West branch
and Firth lake. Neither termination was found, on account of the swampy
or sandy character of the country, so that the present representation
may not be complete. Just east of L’Africain lake there are some
diabases which may be continuations of it, but owing to their altered
appearance they could not be distinguished with certainty in the field
from similar Keewatin forms. Along Duncan lake it appears to represent
the edge of a sill about 300 feet thick lying in the bedding plane of
the Huronian sediments which lie both above and beneath it. From the
attitude of the latter the sill is believed to dip eastward at an angle
of 30 or 40 degrees. The exposed width is usually less than in the
Gowganda area and its composition is more homogeneous, but at the wider
portions the same intermingling of basic and acid phases and aplite
dikes obtains, as for example where it crosses Wapus creek. The full
extent of that portion which extends north-westward from Mosher lake is
not known. The formation at that point is obscured by gravelly soil; it
appears, however, to be unusually wide and well differentiated. An
apparently large body of diabase lies between the north part of Duncan
lake and the West branch. The mapping of this was left incomplete, so
that its total southern extent cannot be given. Its northern part
presents nothing unusual, but about Vipond lake a syenitic phase is
developed, probably indicating a mingling of differentiated rock
varieties as at Gowganda lake or Wapus creek.
The remaining diabase bodies are dikes. Probably these are very numerous
and widespread, but this can only be determined by work of much more
widespread nature than the economic possibilities of such an
investigation warrant at present. They are most frequently seen in the
Laurentian, probably not so much because they are more numerous there,
but because they are more conspicuous in the granites than in the
Keewatin schists and Huronian, from which they differ less in colour.
They attain widths of 60, 100 or more feet, in which cases the texture
is like that of the large masses, but differentiated types and aplite
dikes do not seem to accompany them. The smaller dikes, diminishing to a
width of 1 foot, are compact black rocks of microcrystalline habit, but
like the gabbroid varieties mineralogically.
_Age._—The time of intrusion of these rocks can only be defined as
post-Huronian or post Middle Huronian, there being no younger formations
with which to correlate them. They are identical with the diabase in
other parts of the Montreal River region and of Cobalt. As already noted
the larger masses have produced very limited metamorphic changes in the
adjoining rocks, developing incipient adinole zones in the Huronian
greywackes, besides hardening and fracturing them. Usually the contact
edge of the diabase has been deeply eroded along with the adjoining rock
to form narrow ravines, but wherever it persists a slight chilling is
perceptible. The fine grained edges are much more apparent in dikes
where the mass of hot material being much less was more susceptible to
the influence of cold surroundings. The intrusive nature is also
demonstrated by angular blocks of Huronian materials enclosed within the
diabase, instances of which may be seen on Wapus creek.
_Olivine Diabase._
At the first rapid above Kenisheong lake the Huronian is cut by a broad
dike of different character from those belonging to the quartz-diabase
intrusion. It is a remarkably fresh compact rock of dark grey colour and
medium texture in which an ophitic structure is prominent, acicular
prisms of glassy feldspar penetrating the dark main mass. Its density is
2·991. Under the microscope it is holocrystalline and the constituent
minerals occur in only one generation. The constituents as determined by
linear measurements were found to be plagioclase, 67·5 per cent;
olivine, 14 per cent; augite, 1·5 per cent; iron ore, probably ilmenite,
5 per cent; apatite, 1·8 per cent; biotite, 1·3 per cent; and zircon,
0·03 per cent. The rock is remarkably fresh, even the olivine showing no
signs of decomposition. The plagioclase was determined by optical
methods to be a labradorite of the composition Ab 1 An 1. It forms
laths, twinned according to albite, pericline and carlsbad laws, which
penetrate the ferromagnesian minerals. A few large crystals show fine
zonary lamellation. Olivine is in idiomorphic or rounded grains,
occasionally bordered by a little rim of biotite, possibly a product of
reaction during the period of crystallization. The augite is reddish
brown in colour and later than either olivine or plagioclase, filling
the interstices between the feldspar laths. Irregular masses of black
iron ore, probably ilmenite, are scattered throughout the section, in
some cases showing good crystal forms. A deep brown strongly pleochroic
biotite with a very small optical angle occurs accessorily in small
shreds. Apatite is mostly in slender but sometimes stout hexagonal
prisms. Minute crystals of zircon are rare.
The rock may be designated an olivine diabase of markedly fresh aspect.
It penetrates the Huronian, but judging by its unusually fresh condition
it must be comparatively young.
PLEISTOCENE.
The present glaciated pre-Cambrian surface is scantily covered by
unconsolidated glacial sands and gravel which are being collected by
natural agencies from the hills and more elevated parts into the
depressions. As a consequence the hills are bare, while the valleys and
ravines are soil-filled and support a strong forest growth. Neither sand
nor gravel show signs of stratified arrangement. They play an
unimportant part in the topographical appearance of the country; the
only elevation composed of such materials being a small gravel hill to
the east of Porphyry lake. Between that point and the hills near Mosher
lake is a considerable extent of flat sandy country, the gentle contour
of which contrasts with that of the surrounding hills.
A rather peculiar low apron of sand occupies the very end of the
peninsula between Duncan lake and the West branch. It is of small
extent, and is probably due to river deposition, the West branch at this
point being sluggish and the surface of the sand showing indications of
shifting stream beds.
An extensive area of sand lies at the end of Duncan lake, from whence it
extends northward for several miles, also westward and south-westward
toward the 550 foot hill shown on the map. Seen from any neighbouring
hill this plain appears flat in comparison with the ordinary surface of
the country. It consists of a fine, yellowish, unstratified sand. The
several brooks crossing it are distinguished from those of other parts
of the country by their tortuous courses which are constantly changing,
and which render them unfit for canoe travel. The shallow character and
sandy shores at the north end of Duncan lake have been caused largely by
the transportation of sand into it by these brooks.
Glacial boulders are scattered over the whole district.
ECONOMIC GEOLOGY.
SILVER.
DISTRIBUTION.
With the knowledge acquired from exploitation of James township, and
other of the more recently discovered silver-cobalt camps, prospectors
in the Montreal River district gave exclusive attention to the diabase
formation, recognizing it to be closely connected with mineralizations
of this kind. Some work was done in 1907 and more in the following
season, with the result that on August 4, the first native silver
discoveries were made, almost simultaneously and at short distances
apart, by Messrs. Mann and Dobie, in the diabase just west of Gowganda
lake. The remarkably rich surface showings at once attracted the
attention of the whole prospecting body in the Elk Lake country, and an
activity began which, since the spreading of information to outside
points, has developed into a ‘rush’ of large dimensions.
The known silver bearing area is restricted as yet to about ten square
miles lying between Gowganda lake and the portage route from Elkhorn to
Firth lakes, and is commonly known as Gowganda. Extensive prospecting
only commenced in September, about the close of the field season, so
that only the earlier discoveries are known to the writer, and a
knowledge of the surface details could only be derived by examination of
the few beginnings of patient and continued exploration by claim owners.
The present account must accordingly be accepted as incomplete and by no
means representing the present status of the Gowganda camp.
SURFACE INDICATIONS.
Conditions in the region are such as to demand exploration of the
closest and most intensive order, for the indications of mineralization
are negative rather than positive in character. The Gowganda area was
entirely forested at the beginning of 1908, and a carpet of moss and
vegetable mould covered most of the rock surface. Glacial materials are
also fairly abundant, and sometimes thick enough to render surface
exploration arduous and expensive. Added to this the veins are eroded
more deeply than the country rock, and are represented at the surface by
crevices filled with soil, and thereby rendered inconspicuous. Were the
country a flat one the difficulties in the way of successful prospecting
would be very serious, but fortunately it is rugged, especially near the
diabase. Steep ridges of this material are a regular topographical
feature. The sides of these ridges are bare or readily exposed and offer
fine opportunities for examination. It is significant that the first
silver discoveries were made in the sides of such rock walls. The pink
bloom found at the surfaces of the veins and the adjacent country rock
is also an indicator whose value is fully understood by those working in
the region.
STRUCTURE OF VEINS.
The deposits are in the form of well-defined veins occupying fissures in
the diabase. The amount of surface work done in September was not enough
to throw much light on the continuity of the veins, but a few had been
traced for distances of 300 or 400 feet, and in one case across several
contiguous mining claims, so that they may be said to occupy persistent
fissures. They vary in width from 1ʺ up to 20ʺ. Little could be learned
concerning their attitudes except where they traverse hillsides; in such
cases they are approximately vertical. It is not yet known whether any
regularity exists in their arrangement, but some extend east and west
while others are north and south. The diabase shows no signs of
extensive deformation, all geological evidence indicating that since its
solidification its history has been uneventful, yet the cracks which the
veins occupy appear too persistent to be the result of contraction by
cooling. Besides the strong veins there are others of the gash type, but
the latter are small, not very continuous and poorly or not at all
mineralized.
COMPOSITION OF VEINS.
From comparison of veins at Gowganda, Duncan lake, and Wapus creek a
general uniformity of structure, though not of mineralization, is found
to obtain. The whole mineral association is not found in any one vein,
nor are the relative proportions either of ore or gangue at all
constant. The gangue minerals are quartz and calcite, always mutually
arranged in definite manner. The sides of the veins are composed of
white quartz, which may form only an insignificant coating on the walls
or may occupy nearly the whole space, but in all cases there remains a
central cavity into which the pointed ends of quartz crystals project
freely. At the surface this central portion is empty owing to
weathering, but farther down it is filled by calcite. Veins with
predominant quartz filling seem especially abundant in the Huronian
adjacent to the diabase. The rich veins near Gowganda, so far as
ascertainable, are poor in quartz.
Practically all of them carry chalcopyrite either as diffuse grains or
in considerable amounts. Pyrite is equally abundant but less constant.
Galena is not uncommon. All these occur with the quartz; their presence
in the calcite is not certainly known. Many of the veins show diffuse
stains of reddish pink colour due to cobalt bloom, which though not in
itself of value is important as a sign of the existence of smaltite from
which it is formed by oxidation. The minerals enumerated thus far are
widespread, but economically insignificant; the silver-cobalt
association is present in some cases, however. Little opportunity
existed in 1908 for favourable study of these minerals, so that only a
list of those found at the surface can be given. There native silver,
argentite, smaltite and cobalt bloom have been found, and a few feet
down small lumps of native bismuth. Because they occur either in calcite
or in loose decomposition materials filling the space which the calcite
formerly occupied they are believed to be associated with that gangue.
Infrequently gangue minerals are almost absent and the vein filled by
massive ore.
LOCAL DISTRIBUTION.
Valuable argentiferous veins were known in 1908 only in the Gowganda
district, and, so far as yet known, discoveries have been confined to
the diabase west of that lake. Most of them occur in the southern
portion of the central diabase strip which lies a short distance from
the shore and extends northward for about seven miles from Elkhorn lake.
On one of the Mann claims (T.R. 1966), now owned by Messrs. Foster, an
east and west vein averaging 4ʺ or 5ʺ in width had been traced for 300
feet, the original discovery being made in the exposed face of a low
diabase wall. At its surface the vein material had been weathered out
for a depth of about 15ʺ and the cavity filled by a brownish mass of the
decomposed matter mixed with vegetable mould and sand. Nuggets of mossy
or arborescent silver were scattered richly through this dirt, and a
fairly continuous spine of the same metal, sometimes an inch thick,
extended along the middle of the crevice. A test pit sunk about 8 feet,
but barricaded at the time of the writer’s visit, had exposed, according
to Mr. Mann, silver and smaltite in a calcite vein. On the adjoining
claim (T.R. 1982), a vein of massive smaltite about 1ʺ wide was seen; a
little silver had been found at its surface and streaks of argentite and
disseminated grains of smaltite were seen in the wall rock. Aplite dikes
on another claim were found to be stained by cobalt bloom, and full of
disseminated chalcopyrite.
The properties owned by Messrs. Crawford and Dobie about half a mile
farther south were not visited, but were generally reported to be of
about the same richness as that in T.R. 1966. Immediately north of
Hanging-stone lake Mr. F. A. McIntosh was conducting active prospecting
in a coarse gabbroid, locally syenitic, form of the diabase, intersected
by aplite dikes. A discovery of native silver has been made since then
and the property sold to Messrs. F. R. Bartlett & Co., of Toronto,
together with other claims located between the north-east and north-west
arms. Other discoveries are reported just south-east, also a short
distance north of Milne lake.
No silver had been obtained in the eastern diabase strip, although the
geological conditions appear identical and calcite veins are abundant.
An exceptionally large vein, about 18ʺ wide, and traceable across two
adjoining claims was seen on the property of Messrs. McLaughlin and
McIntosh, about half a mile north-east of the north-west arm.
Mineralization in it near the surface was very slight. Several veins
carrying small amounts of chalcopyrite, pyrite, bloom and smaltite were
seen on the properties of Messrs. Elstone and Reilly (T.R. 1961, 1962
and 1903). In one of them small amounts of bismuth are present; another
contains an unusually heavy black substance which proved to be calcite
filled with minute crystals of magnetite.
In the western strip less exploration had been performed and little
could be learned about the ore deposits. Loose pieces of native silver
had been found by W. H. Margueratt in narrow fissures on M.R. 1798, but
the vein material was not exposed.
Outside the Gowganda area systematic prospecting was in progress at only
one point—Wapus creek. Under the management of Mr. Robert Lett a group
of nine claims was being stripped and trenched, with the result that
numerous calcite veins had been traced through a diabase showing the
same complex intermingling of basic and acid phases and aplite dikes as
at Gowganda. Chalcopyrite and cobalt bloom were abundant, and smaltite
had been found as disseminations in the wall rock. Lumps of native
bismuth weighing several ounces had been taken from a fissure in an
aplite dike, analyses of which showed it to contain silver.
Tentative exploration was being conducted along Duncan lake and east of
Firth lake, but not with the closeness and persistence which the
topography of these veins require. In general the veins seen on Duncan
lake are exceptionally rich in quartz, and gash veins are common.
Chalcopyrite, pyrite and galena are the most noticeable metalliferous
minerals, but cobalt bloom stains are frequently observable. So far as
known no attention has been given to the large diabase body between
Duncan lake and the West branch, although its size and varied
composition are thought to make it a desirable prospecting ground.
FUTURE POSSIBILITIES.
The present knowledge of the Gowganda area indicates it to be highly
mineralized, at least in so far as number of veins and surface showings
are concerned. The number of discoveries within its area of ten square
miles is steadily increasing. The area, character of the mineral
association and the richness of the surface showings are comparable with
those of Cobalt. There is a general similarity in the geological
conditions. The mineralized veins in Gowganda occur in the diabase as do
some of the good Cobalt veins. There are, it is true, local differences,
but the resemblances are more pronounced than the differences and lead
to the hope that exploitation will reveal similar underground
conditions. The well mineralized veins are sufficiently long and uniform
on the surface to suggest similarly persistent vertical dimensions.
Further geological work may reveal something definite concerning the
character and size of the diabase bodies which form the country rock,
and thus afford a basis for predicting their subterranean distribution.
While there are grounds for hoping that the veins will persist in depth,
this has not yet been proved, nor, if this is the case, that the
mineralization and values are also persistent.
The relative importance of Gowganda is therefore a matter of uncertainty
as yet, but it may be confidently affirmed that for its state of
development the outlook is very favourable, and the number of veins,
area of mineralization and rich surface showings afford good grounds for
hoping that some at least of the veins will be found to be commercially
important.
The details of igneous intrusion, differentiation and mineralization may
never be sufficiently understood to allow of accurate prediction
regarding the location of silver deposits, but a general conception of
the sequence of events culminating in their formation does permit of the
formulation of certain criteria useful in the search for ores. Evidence
is accumulating to show that the silver-cobalt mineralizations in the
Timiskaming region are connected with a late stage of differentiation in
the magma which supplied the quartz diabase and aplite. It seems
reasonable, therefore, to anticipate ore deposits in or near such
bodies, especially if they are of large size and have undergone
important chemical differentiation, that is, if they contain a varied
and extensive association of basic and acid phases of the diabase.
Pre-existing channels to receive the mineralizers are also necessary and
their distribution a matter of vital importance, but in this region they
appear to have been everywhere abundant.
These conditions appear to exist quite as fully at several other
localities besides Gowganda. At Wapus creek they seem identical and,
indeed, results obtained thus far indicate that some mineralization of
the silver-cobalt type exists. Between Duncan lake and the West branch
the conditions require further study, but, as now known, are not
discouraging.
COPPER.
The chalcopyrite, which seems a much more constant constituent of the
veins associated with the quartz diabase, is sometimes aggregated into
bunches which yield ore specimens of such excellent appearance as to
arouse interest. The ore is, however, confined to veins a few inches in
width and so scattered as to render them valueless. Occurrences of this
kind characterize most of the great diabase bodies, examples of which
occur on Mosher lake, between the North-east and North-west arms of
Gowganda lake and elsewhere. The chalcopyrite is sometimes superficially
altered to malachite and azurite.
IRON ORE.
_Hematite._—Excellent specular and kidney ore is known to exist a short
distance east of Nest lake, but the locality was not visited owing to
the more urgent requirements of other portions of the district.
Specimens of the ore obtained, however, proved to be of excellent
character, with little admixture of silica or other foreign matter. The
ore body is thought to be of vertical tabular form, occupying a
fissure-like space. Its limits are not known, consequently nothing can
be yet stated regarding the commercial possibility of the deposit.
Specular ore was seen on mining claim T.R. 2009, near the north-east end
of Firth lake, occupying a fissure in the Keewatin. The ore is of good
quality, but the outcrop is of insignificant size, the fissure being
only about 2 feet wide, and no ore occurring in either the chlorite
schist or reddish granite which lie on either side.
Specular ore also occurs in the basal conglomerate of the Huronian
series, filling the interstices between the pebbles where an original
cement was deficient. At the south end of Kenisheong lake the
conglomerate appears at the water’s edge, and the hematite may be
observed while paddling near shore. The same thing occurs at the narrows
on Duncan lake, just south of the central expansion. In neither case is
the ore in commercially valuable quantity.
_Magnetite._—Keewatin iron formation exists about one-half mile to the
north-east of Gowganda lake. A brief visit was paid to some claims
belonging to Mr. Cryderman where the formation is well exposed. The
Keewatin, which is partially overlain by Huronian and traversed by
diabase, consists of dark grey or black, banded chert or quartzite
associated with chlorite schist. The dark bands, usually only a few
inches in width, are full of disseminated magnetite grains. No
concentrations were noticed and the richest bands would probably yield
less than 30 per cent metallic iron, consequently the present showings
cannot be considered valuable.
ASBESTOS.
_Distribution._
In the Keewatin area between Firth and Obushkong lakes there occur
masses of a basic igneous rock through whose decomposition serpentine
and asbestos have been developed. The localities given in connexion with
the description of the Keewatin may be briefly restated. Two bodies were
found. One of these, lying east of Foot lake and 20 chains from
Obushkong was traced for a width of 4 chains, but nothing learned of its
north and south extent. It consists very largely of green serpentine
traversed by a network of fine, white weathering veins of asbestos. More
extensive outcrops exist along the east shore of Firth lake. At somewhat
more than a mile from the foot of the lake and near a small log shack at
the water’s edge a considerable mass of partially decomposed wehrlite,
serpentine, and asbestos is visible. The main mass is of dark green
colour, the asbestos traversing it abundantly as a series of glistening
bright green threads. The seams are small, none being found more than
1/4ʺ in width, but the asbestos fibres are fine and elastic. The
serpentine is often coarsely fibrous but brittle.
ORIGIN.
Microscopic examination shows the serpentine and asbestos to be the
product of decomposition of the wehrlite, a nearly black medium grained
igneous type. Alteration has obscured its original character, but
sufficient of the primary constituents remain to admit of its
determination. It consisted of olivine, diallage, and common hornblende,
with considerable ilmenite and apatite, but plagioclase is apparently
absent. Hornblende and diallage form the basis of the section in which
lie abundant rounded or idiomorphic grains of olivine. The latter is
completely altered to a matted intergrowth of fibrous serpentine
containing scattered grains of black iron ore. Diallage persists as
colourless bi-refringent remnants enclosed by a felted mass of
decomposition products, chiefly long scales of talc. The hornblende is
fresher and strongly pleochroic, the tints being green; its alteration
begins by bleaching, followed by development of colourless fibres of low
bi-refringence, possibly serpentine. Primary ilmenite is replaced by
irregular patches of leucoxene, showing gridiron structure. The final
product of alteration is a soft green serpentine rock composed almost
wholly of that mineral.
The limits of these masses are exceedingly difficult to define, owing to
the fact that they are associated with other Keewatin rock and basic
forms of the post-Huronian diabase, to which it presents considerable
resemblance. The asbestos actually seen is probably too short and small
in amount to be valuable, but the high commercial value of this material
renders delimitation of the wehrlite masses advisable. Asbestos of very
good quality has been found by Mr. George Rahn in the vicinity of
Sinclair mountain, so that this mineral may be one of the district’s
latent resources.
CANADA
DEPARTMENT OF MINES
GEOLOGICAL SURVEY BRANCH
HON. W. TEMPLEMAN, MINISTER; A. P. LOW, LL.D., DEPUTY MINISTER;
R. W. BROCK, DIRECTOR.
----------------------------------------------------------------
SELECTED LIST OF REPORTS AND MAPS
(SINCE 1885)
OF SPECIAL ECONOMIC INTEREST
PUBLISHED BY
THE GEOLOGICAL SURVEY BRANCH
* Publications marked thus are out of print.
Reports of the Mines Section—
No. 245. Report of Mines Section for 1886.
272. " " 1887.
300. " " 1888.
301. " " 1889.
334. " " 1890.
335. " " 1891.
360. " " 1892.
572. " " 1893-4.
602. " " 1895.
625. " " 1896.
662. " " 1897.
698. " " 1898.
718. " " 1899.
744. " " 1900.
800. " " 1901.
835. " " 1902.
893. " " 1903.
928. " " 1904.
971. " " 1905.
Mineral Production of Canada—
No. 414. For 1886.
415. " 1887.
416. " 1888.
417. " 1889.
418. " 1890.
419. " 1891.
420. " 1886-91.
421. " 1892.
422. " 1893.
555. " 1894.
577. " 1895.
612. " 1896.
623. " 1886-96.
640. " 1897.
671. " 1898.
686. " 1899.
719. " 1900.
719a. " 1901.
813. " 1902.
861. " 1903.
896. " 1904.
924. " 1905.
981. " 1906.
Mineral Resources Bulletins—
No. *818. Platinum.
851. Coal.
*854. Asbestos.
857. Infusorial Earth.
858. Manganese.
859. Salt.
860. Zinc.
869. Mica.
872. Molybdenum and Tungsten.
877. Graphite.
880. Peat.
881. Phosphate.
882. Copper.
913. Mineral Pigments.
953. Barytes.
984. Mineral Pigments (French).
Reports of the Section of Chemistry and Mineralogy—
No. *102. For 1874-5.
*110. " 1875-6.
*119. " 1876-7.
126. " 1877-8.
138. " 1878-9.
148. " 1879-80.
156. " 1880-1-2.
169. " 1882-3-4.
222. " 1885.
246. " 1886.
273. " 1887-8.
299. " 1888-9.
333. " 1890-1.
359. " 1892-3.
580. " 1894.
616. " 1895.
651. " 1896.
695. " 1898.
724. " 1899.
821. " 1900.
*958. " 1906.
745. Altitudes of Canada, by J. White. 1899.
*972. Descriptive Catalogue of Minerals and Rocks, by R. A. A. Johnston
and G. A. Young.
YUKON.
*260. Yukon district, by G. M. Dawson. 1887. Maps Nos. 274, scale 60 m.
= 1 in.; 275-277, scale 8 m. = 1 in.
295. Yukon and Mackenzie basins, by R. G. McConnell. 1889. Map No. 304,
scale 48 m. = 1 in.
687. Klondike gold fields (preliminary), by R. G. McConnell. 1900. Map
No. 688, scale 2 m. = 1 in.
884. Klondike gold fields, by R. G. McConnell. 1901. Map No. 772, scale
2 m. = 1 in.
*909. Windy Arm, Tagish lake, by R. G. McConnell. 1906. Map No. 916,
scale 2 m. = 1 in.
943. Upper Stewart river, by J. Keele. Map No. 938, }
scale 8 m. = 1 in. }
} Bound together.
951. Peel and Wind rivers, by Chas. Camsell. Map No. }
942, scale 8 m. = 1 in. }
979. Klondike gravels, by R. G. McConnell. Map No. 1011, scale 40 ch. =
1 in.
982. Conrad and Whitehorse mining districts, by D. D. Cairnes. 1901. Map
No. 990, scale 2 m. = 1 in.
1016. Klondike Creek and Hill gravels, by R. G. McConnell. (French). Map
No. 1011, scale 40 ch. = 1 in.
BRITISH COLUMBIA.
212. The Rocky mountains (between latitudes 49° and 51° 30ʹ), by G. M.
Dawson. 1885. Map No. 223, scale 6 m. = 1 in. Map No. 224, scale 1-1/2
m. = 1 in.
*235. Vancouver island, by G. M. Dawson. 1886. Map No. 247, scale 8 m. =
1 in.
236. The Rocky mountains, geological structure, by R. G. McConnell.
1886. Map No. 248, scale 2 m. = 1 in.
263. Cariboo mining district, by A. Bowman. 1887. Maps Nos. 278-281.
*271. Mineral wealth, by G. M. Dawson.
*294. West Kootenay district, by G. M. Dawson. 1888-9. Map No. 303,
scale 8 m. = 1 in.
*573. Kamloops district, by G. M. Dawson. 1894. Maps Nos. 556-7, scale 4
m. = 1 in.
574. Finlay and Omineca rivers, by R. G. McConnell. 1894. Map No. 567,
scale 8 m. = 1 in.
743. Atlin Lake mining division, by J. C. Gwillim. 1899. Map No. 742,
scale 4 m. = 1 in.
939. Rossland district, by R. W. Brock. Map No. 941, scale 1,600 ft. = 1
in.
940. Graham island, by R. W. Ells. 1905. Map No. 921, scale 4 m. = 1
in., and Map No. 922, scale 1 m. = 1 in.
986. Similkameen district, by Chas. Camsell. Map. No. 987, scale 400 ch.
= 1 in.
988. Telkwa river and vicinity, by W. W. Leach. Map No. 989, scale 2 m.
= 1 in.
996. Nanaimo and New Westminster districts, by O. E. LeRoy. 1907. Map
No. 997, scale 4 m. = 1 in.
ALBERTA.
*237. Central portion, by J. B. Tyrrell. 1886. Maps Nos. 249 and 250,
scale 8 m. = 1 in.
324. Peace and Athabaska Rivers district, by R. G. McConnell. 1890-1.
Map No. 336, scale 48 m. = 1 in.
703. Yellowhead Pass route, by J. McEvoy. 1898. Map No. 676, scale 8 m.
= 1 in.
949. Cascade coal-field, by D. B. Dowling. Maps (8 sheets) Nos. 929-936,
scale 1 m. = 1 in.
968. Moose Mountain district, by D. D. Cairnes. Maps No. 963, scale 2 m.
= 1 in.; No. 966, scale 1 m. = 1 in.
SASKATCHEWAN.
213. Cypress hills and Wood mountain, by R. G. McConnell. 1885. Maps
Nos. 225 and 226, scale 8 m. = 1 in.
601. Country between Athabaska lake and Churchill river, by J. B.
Tyrrell and D. B. Dowling. 1895. Map No. 957, scale 25 m. = 1 in.
868. Souris River coal-field, by D. B. Dowling. 1902.
MANITOBA.
264. Duck and Riding mountains, by J. B. Tyrrell. 1887-8. Map No. 282,
scale 8 m. = 1 in.
296. Glacial Lake Agassiz, by W. Upham. 1889. Maps Nos. 314, 315, 316.
325. North-western portion, by J. B. Tyrrell. 1898. Maps Nos. 339 and
350, scale 8 m. = 1 in.
704. Lake Winnipeg (west shore), by D. B. Dowling. }
1898. Map No. 664, scale 8 m. = 1 in. }
} Bound together.
705. Lake Winnipeg (east shore), by J. B. Tyrrell. }
1898. Map No. 664, scale 8 m. = 1 in. }
NORTH WEST TERRITORIES.
217. Hudson bay and strait, by R. Bell. 1885. Map No. 229, scale 4 m. =
1 in.
238. Hudson bay, south of, by A. P. Low. 1886.
239. Attawapiskat and Albany rivers, by R. Bell. 1886.
244. Northern portion of the Dominion, by G. M. Dawson. 1886. Map No.
255, scale 200 m. = 1 in.
267. James bay and country east of Hudson bay, by A. P. Low.
578. Red lake and part of Berens river, by D. B. Dowling. 1894. Map No.
576, scale 8 m. = 1 in.
*584. Labrador peninsula, by A. P. Low. 1895. Maps Nos. 585-588, scale
25 m. = 1 in.
618. Dubawnt, Kazan and Ferguson rivers, by J. B. Tyrrell. 1896. Map No.
603, scale 25 m. = 1 in.
657. Northern portion of the Labrador peninsula, by A. P. Low.
680. South Shore Hudson strait and Ungava bay, by A. P. }
Low. Map No. 699, scale 25 m. = 1 in. }
} Bound together.
713. North Shore Hudson strait and Ungava bay, by R. }
Bell. Map No. 699, scale 25 m. = 1 in. }
725. Great Bear lake to Great Slave lake, by J. M. Bell. 1900.
778. East Coast Hudson bay, by A. P. Low. 1900. Maps Nos. 779, 780, 781,
scale 8 m. = 1 in.
786-787. Grass River region, by J. B. Tyrrell and D. B. Dowling. 1900.
815. Ekwan river and Sutton lakes, by D. B. Dowling. 1901. Map No. 751,
scale 50 m. = 1 in.
819. Nastapoka islands, Hudson bay, by A. P. Low. 1900.
905. The Cruise of the _Neptune_, by A. P. Low. 1905.
ONTARIO.
215. Lake of the Woods region, by A. C. Lawson. 1885. Map No. 227, scale
2 m. = 1 in.
*265. Rainy Lake region, by A. C. Lawson. 1887. Map No. 283, scale 4 m.
= 1 in.
266. Lake Superior, mines and mining, by E. D. Ingall. 1888. Maps Nos.
285, scale 4 m. = 1 in.; 286, scale 20 ch. = 1 in.
326. Sudbury mining district, by R. Bell. 1890-1. Map No. 343, scale 4
m. = 1 in.
327. Hunter island, by W. H. C. Smith. 1890-1. Map No. 342, scale 4 m. =
1 in.
332. Natural Gas and Petroleum, by H. P. H. Brumell. 1890-1. Maps Nos.
344-349.
357. Victoria, Peterborough and Hastings counties, by F. D. Adams.
1892-3.
627. On the French River sheet, by R. Bell. 1896. Map No. 570, scale 4
m. = 1 in.
678. Seine river and Lake Shebandowan map-sheets, by W. McInnes. 1897.
Maps Nos. 589 and 560, scale 4 m. = 1 in.
723. Iron deposits along Kingston and Pembroke railway, by E. D. Ingall.
1900. Map No. 626, scale 2 m. = 1 in; and plans of 13 mines.
739. Carleton, Russell and Prescott counties, by R. W. Ells. 1899. (See
No. 739, Quebec.)
741. Ottawa and vicinity, by R. W. Ells. 1900.
790. Perth sheet, by R. W. Ells. 1900. Map No. 789, scale 4 m. = 1 in.
961. Sudbury Nickel and Copper deposits, by A. E. Barlow. (Reprint).
Maps Nos. 775, 820, scale 1 m. = 1 in.; 824, 825, 864, scale 400 ft. =
1 in.
962. Nipissing and Timiskaming map-sheets, by A. E. Barlow. (Reprint).
Maps Nos. 599, 606, scale 4 m. = 1 in.; No. 944, scale 1 m. = 1 in.
965. Sudbury Nickel and Copper deposits, by A. E. Barlow. (French).
970. Report on Niagara Falls, by J. W. Spencer. Maps Nos. 926, 967.
977. Report on Pembroke sheet, by R. W. Ells. Map No. 660, scale 4 m. =
1 in.
992. Report on North-western Ontario, traversed by National
Transcontinental railway, between Lake Nipigon and Sturgeon lake, by
W. H. Collins. Map No. 993, scale 4 m. = 1 in.
998. Report on Pembroke sheet, by R. W. Ells. (French). Map No. 660,
scale 4 m. = 1 in.
QUEBEC.
216. Mistassini expedition, by A. P. Low. 1884-5. Map No. 228, scale 8
m. = 1 in.
240. Compton, Stanstead, Beauce, Richmond and Wolfe counties, by R. W.
Ells. 1886. Map No. 251 (Sherbrooke sheet), scale 4 m. = 1 in.
268. Megantic, Beauce, Dorchester, Levis, Bellechasse and Montmagny
counties, by R. W. Ells. 1887-8. Map No. 287, scale 40 ch. = 1 in.
297. Mineral resources, by R. W. Ells. 1889.
328. Portneuf, Quebec and Montmagny counties, by A. P. Low. 1890-1.
579. Eastern Townships, Montreal sheet, by R. W. Ells and F. D. Adams.
1894. Map No. 571, scale 4 m. = 1 in.
591. Laurentian area north of the Island of Montreal, by F. D. Adams.
1895. Map No. 590, scale 4 m. = 1 in.
670. Auriferous deposits, South-eastern portion, by R. Chalmers. 1895.
Map No. 667, scale 8 m. = 1 in.
707. Eastern Townships, Three Rivers sheet, by R. W. Ells. 1898.
739. Argenteuil, Ottawa and Pontiac counties, by R. W. Ells. 1899. (See
No. 739, Ontario).
788. Nottaway basin, by R. Bell. 1900. *Map No. 702, scale 10 m. = 1 in.
863. Wells on Island of Montreal, by F. D. Adams. 1901. Maps Nos. 874,
875, 876.
923. Chibougamau region, by A. P. Low. 1905.
962. Timiskaming map-sheet, by A. E. Barlow. (Reprint). Maps Nos. 599,
606, scale 4 m. = 1 in.; 944, scale 1 m. = 1 in.
974. Report on Copper-bearing rocks of Eastern Townships, by J. A.
Dresser. Map No. 976, scale 8 m. = 1 in.
975. Report on Copper-bearing rocks of Eastern Townships, by J. A.
Dresser. (French).
998. Report on the Pembroke sheet, by R. W. Ells. (French).
1028. Report on a Recent Discovery of Gold near Lake Megantic, Que., by
J. A. Dresser. Map No. 1029, scale 2 m. = 1 in.
1032. Report on a Recent Discovery of Gold near Lake Megantic, Que., by
J. A. Dresser. (French). Map No. 1029, scale 2 m. = 1 in.
NEW BRUNSWICK.
218. Western New Brunswick and Eastern Nova Scotia, by R. W. Ells. 1885.
Map No. 230, scale 4 m. = 1 in.
219. Carleton and Victoria counties, by L. W. Bailey. 1885. Map No. 231,
scale 4 m. = 1 in.
242. Victoria, Restigouche and Northumberland counties, N.B., by L. W.
Bailey and W. McInnes. 1886. Map No. 254, scale 4 m. = 1 in.
269. Northern portion and adjacent areas, by L. W. Bailey and W.
McInnes. 1887-88. Map No. 290, scale 4 m. = 1 in.
330. Temiscouata and Rimouski counties, by L. W. Bailey and W. McInnes.
1890-1. Map No. 350, scale 4 m. = 1 in.
661. Mineral resources, by L. W. Bailey. 1897. Map No. 675, scale 10 m.
= 1 in. New Brunswick geology, by R. W. Ells. 1887.
799. Carboniferous system, by L. W. Bailey. 1900. }
} Bound together.
803. Coal prospects in, by H. S. Poole. 1900. }
983. Mineral resources, by R. W. Ells. Map No. 969, scale 16 m. = 1 in.
NOVA SCOTIA.
243. Guysborough, Antigonish, Pictou, Colchester and Halifax counties,
by Hugh Fletcher and E. R. Faribault. 1886.
331. Pictou and Colchester counties, by H. Fletcher. 1890-1.
358. South-western Nova Scotia (preliminary), by L. W. Bailey. 1892-3.
Map No. 362, scale 8 m. = 1 in.
628. South-western Nova Scotia, by L. W. Bailey. 1896. Map No. 641,
scale 8 m. = 1 in.
685. Sydney coal-field, by H. Fletcher. Maps Nos. 652, 653, 654, scale 1
m. = 1 in.
797. Cambrian rocks of Cape Breton, by G. F. Matthew. 1900.
871. Pictou coal-field, by H. S. Poole. 1902. Map No. 833, scale 25 ch.
= 1 in.
MAPS.
1042. Dominion of Canada. Minerals. Scale 100 m. = 1 in.
YUKON.
805. Explorations on MacMillan, Upper Pelly and Stewart rivers, scale 8
m. = 1 in.
891. Portion of Duncan Creek Mining district, scale 6 m. = 1 in.
894. Sketch Map Kluane Mining district, scale 6 m. = 1 in.
916. Windy Arm Mining district, Sketch Geological Map, scale 2 m. = 1
in.
991. Tantalus and Five Fingers coal mines, scale 1 m. = 1 in.
BRITISH COLUMBIA.
278. Cariboo Mining district, scale 2 m. = 1 in.
604. Shuswap Geological sheet, scale 4 m.= 1 in.
771. Preliminary Edition, East Kootenay, scale 4 m.= 1 in.
767. Geological Map of Crowsnest coal-fields, scale 2 m. = 1 in.
791. West Kootenay Minerals and Striæ, scale 4 m. = 1 in.
792. West Kootenay Geological sheet, scale 4 m. = 1 in.
828. Boundary Creek Mining district, scale 1 m.= 1 in.
890. Nicola Coal basins, scale 1 m. = 1 in.
941. Preliminary Geological Map of Rossland and vicinity, scale 1,600
ft. = 1 in.
1001. Topographical Map of Rossland, scale 400 ft. = 1 in.
1003. Rossland Mining camp, scale 1,200 ft. = 1 in.
ALBERTA.
594-596. Peace and Athabaska rivers, scale 10 m. = 1 in.
808. Blairmore-Frank coal-fields, scale 180 ch. = 1 in.
892. Costigan coal basin, scale 40 ch. = 1 in.
1010. Coal Areas of Peace and Athabaska rivers, scale 35 m. = 1 in.
MANITOBA.
804. Map of part of Turtle mountain showing coal areas, scale 1-1/2 m. =
1 in.
ONTARIO.
227. Lake of the Woods sheet, scale 2 m. = 1 in.
*283. Rainy Lake sheet, scale 4 m. = 1 in.
*342. Hunter Island sheet, scale 4 m. = 1 in.
343. Sudbury sheet, scale 4 m. = 1 in.
373. Rainy River sheet, scale 2 m. = 1 in.
560. Seine River sheet, scale 4 m. = 1 in.
570. French River sheet, scale 4 m. = 1 in.
589. Lake Shebandowan sheet, scale 4 m. = 1 in.
599. Timiskaming sheet, scale 4 m. = 1 in. (New Edition 1907).
605. Manitoulin Island sheet, scale 4 m. = 1 in.
606. Nipissing sheet, scale 4 m. = 1 in. (New Edition 1907).
660. Pembroke sheet, scale 4 m. = 1 in.
663. Ignace sheet, scale 4 m. = 1 in.
708. Haliburton sheet, scale 4 m. = 1 in.
720. Manitou Lake sheet, scale 4 in. = 1 in.
*750. Grenville sheet, scale 4 m. = 1 in.
770. Bancroft sheet, scale 2 m. = 1 in.
775. Sudbury district, Victoria mines, scale 1 m. = 1 in.
789. Perth sheet, scale 4 m. = 1 in.
820. Sudbury district, Sudbury, scale 1 m. = 1 in.
824-825. Sudbury district, Copper Cliff mines, scale 400 ft. = 1 in.
852. North-east Arm of Vermilion Iron ranges, Timagami, scale 40 ch. = 1
in.
864. Sudbury district, Elsie and Murray mines, scale 400 ft. = 1 in.
903. Ottawa and Cornwall sheet, scale 4 m. = 1 in.
944. Preliminary Map of Timagami and Rabbit lakes, scale 1 m. = 1 in.
964. Geological Map of parts of Algoma and Thunder bay, scale 8 m. = 1
in.
QUEBEC.
251. Sherbrooke sheet, Eastern Townships Map, scale 4 m. = 1 in.
287. Thetford and Coleraine Asbestos district, scale 40 ch. = 1 in.
375. Quebec sheet, Eastern Townships Map, scale 4 m. = 1 in.
571. Montreal sheet, Eastern Townships sheet, scale 4 m. = 1 in.
665. Three Rivers sheet, Eastern Townships Map, scale 4 m. = 1 in.
667. Gold Areas in south-eastern part, scale 8 m. = 1 in.
668. Graphite districts in Labelle county, scale 40 ch. = 1 in.
918. Chibougamau region, scale 4 m. = 1 in.
976. The Older Copper-bearing Rocks of the Eastern Townships, scale 8 m.
= 1 in.
1007. Preliminary Map of townships east of Lake Timiskaming, scale 2 m.
= 1 m.
NEW BRUNSWICK.
675. Map of Principal Mineral Occurrences. Scale 10 m. = 1 in.
969. Map of Principal Mineral Localities. Scale 16 m. = 1 in.
NOVA SCOTIA.
812. Preliminary Map of Springhill coal-field, scale 50 ch. = 1 in.
833. Pictou coal-field, scale 25 ch. = 1 in.
897. Preliminary Geological Plan of Nictaux and Torbrook Iron district,
scale 25 ch. = 1 in.
927. General Map of Province showing gold districts, scale 12 m. = 1 in.
937. Leipsigate Gold district, scale 500 ft. = 1 in.
945. Harrigan Gold district, scale 400 ft. = 1 in.
995. Malaga Gold district, scale 250 ft. = 1 in.
1012. Brookfield Gold district, scale 250 ft. = 1 in.
NOTE.—Individual Maps or Reports will be furnished free to _bona fide_
Canadian applicants.
Applications should be addressed to the Director, Geological Survey
Branch, Department of Mines, Ottawa.
Reports and Maps may be ordered by the numbers prefixed to titles.
Footnote 1:
Sketch map of Abitibi region, 1901. No. 760.
Transcriber’s Note
This book uses inconsistent spelling and hyphenation, which were
retained in the ebook version. Some corrections have been made to the
text, including normalizing punctuation.
Further corrections are noted below:
p. 33: so that withtin an area -> so that within an area
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