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Handbook to Winnipeg and the Province of Manitoba
The Geology of Canada by R. W. Brock, Esq.

FOR an outline of the geology and physical features of Canada. I have thought that nothing better could be presented than the chapter prepared by the late George M. Dawson for the Handbook of Canada issued by the local executive of the British Association for the Toronto meeting. The present sketch is therefore based upon Dawson’s Physical Geography and Geology of Canada, revised and in parts expanded. This has been done with the co-operation of Mr. W. Mclnnes, Mr. R. G. McConnell, Mr. G. A. Young, and Mr. O. E. Leroy.

A great part of Canada is as yet unexplored, and over a large portion only reconnaissance surveys have been made, but enough has been done to establish a correct conception of the general geological structure of the country.

Since the greatest part of Canada is unprospected, we do not know what latent mineral wealth awaits develop ment, but we do know that there is in Canada one of the greatest tracts of unexplored mineral land in the world, and sufficient has already been accomplished to demonstrate that Canada is destined to become one of the great mining countries. .

The development of the mineral resources has been slow, on account of the abundance of excellent agricultural land, which made Canadians an agricultural people. In recent years, however, attention has been directed to its mineral resources, and a mining industry is rapidly developing. In 1886 the mineral production

of Canada was under ten and a quarter million dollars in value, while last year it was eighty-seven million.

This development is making necessary a corresponding increase in the attention given to the study of the geology of the country, so that the knowledge of the geological structure of Canada may be expected to rapidly extend.

Canada embraces the northern half of the continent of North America with its adjacent islands, including those of the Arctic Ocean, between the 141st meridian and Greenland, but exclusive of Alaska in the extreme north west, the island of Newfoundland, which still remains a separate British colony, and the small islands of St. Pierre and Miquelon, retained by France. The total area of Canada is estimated at about 3,729,665 square miles, of which the Arctic islands to the north make up over 500,000 square miles. This area is somewhat larger than the United States (including Alaska), and not much less than all Europe.

The form of the North American continent may be described as that of an isoscles triangle, of which the narrower part, pointing south, constitutes Mexico, a wide central belt, the United States, while the broader base is the Dominion of Canada. The northern margin of the continental land lies approximately on the seventieth parrallel of north latitude, but in the east the land area is continued northward by the great islands of the Arctic archipelago, while south of these the continent is broken into by the large but shallow sea named Hudson Bay, 800 miles from north to south and some 600 miles in width.

Surrounding Hudson Bay lies the Laurentian plateau or “Canadian Shield,” a tract of land underlain by pre-Cambrian rocks and, though relatively elevated, never rising over 2,000 feet above the sea except in the extreme north-east. Spreading widely in the Labrador peninsula, this upland runs with narrow dimensions round the southern extremity of Hudson Bay and thence is continued north-westward to the Arctic Ocean. Along the southern margin of the Laurentian plateau lies the great waterway, the River St. Lawrence, running to the very centre of the continent and expanding there into the group of inland fresh water seas generally spoken of as the Great Lakes, while the Winnipeg system of lakes, with Athabasca, Great Slave and Great Bear Lakes, occupy a very similar position on the outer rim of the north-western extension of the plateau.

Never far distant from the oceans, and following the trends of the south-east and south-west sides of the Laurentian highlands respectively, the Appalachian mountains and those comprised in the western Cordilleras converge to the south, embracing between them, to the south of the Great Lakes, the central plain of the continent that, west of the Laurentian plateau, extends northward through Canada to the Arctic Ocean. But in the east, in Canada, the Appalachian range more clearly follows the border of the Canadian Shield, separated from it, till the Great Lakes are reached, only by the valley of the St. Lawrence River. While the two mountain systems of the continent are, with respect to one another, symmetrically disposed, they are opposed in extent and character. The Cordillerian system of the west embraces a truly mountainous tract, over which large areas are elevated more than 5,000 feet above the sea, with peaks rising to heights of 10,000 feet and more. On the other hand, the mountains or hills of the Appalachian system, in Canada, seldom rise more than 2,000 feet above the sea, and over the greater part of the eastern provinces of New Brunswick, Nova Scotia and Prince Edward Island the land lies below the one thousand foot datum line.

Only the most general notice can be given to the rivers and lakes of Canada, but no feature of the country is more important, whether historically or geographically, than the great length and volume of its principal watercourses and the manner in which these interlock and penetrate almost every part of the area. Besides the St. Lawrence, with its drainage basin of 530,000 square miles, there are three more rivers of the first class of which the watersheds are wholly or in great part included in Canada. These are the Nelson, the Mackenzie and the Yukon. The first-named reaches Hudson Bay, bringing with it the waters of the Saskatchewan and other large and long rivers which drain a vast region in the centre of the continent. Its basin is estimated at 307,000 square miles. The Mackenzie, flowing into the Arctic Ocean, drams not only most of the northern part of the interior plain of the continent, but also considerable portions of the Rocky Mountain region and the Laurentian plateau, with a basin of about 677,000 square miles. Next to the St. Lawrence it is the longest river of Canada, being not less than 1,800 miles from its source to its mouth. The Yukon, discharging into the northern part of Behring Sea, drains a great tract of the northern part of the Cordillerian region comprised in Canada, besides flowing across the whole width of Alaska.

It is only by contrast with these greatest rivers that many more are relegated to a second or third rank, as an examination of a map will show. It will also be apparent that much the larger part of the country lies on the northern slope of the continent regarded as a whole, and that the remainder is divided between the Atlantic and Pacific sides, only an inconsiderable region being tributary to the southward-flowing system of the Missouri and its branches.

tt may be useful in this connection to state the heights of a few of the larger lakes, as ruling features in physical geography. The Great Lakes, although they stand at four levels, m reality occupy only two distinct stages, separated by the Niagara Falls. Below this cataract is Lake Ontario, 246 feet above the sea, above it Lake Erie, 572 feet, Lake Huron and Lake Michigan, 581 feet, and Lake Superior, 602 feet. Further to the west and northwest are Lake of the Woods, 1,057 feet, Lake Winnipeg, 710 feet, Lakes Manitoba and Winnipegosis, 810 and 828 feet respectively, Athabasca Lake, 690 feet, Great Slave Lake about 520 feet, and Great Bear Lake about 390 feet. Each of these lakes marks the lowest level of large tracts of adjacent land.

From a physiographical and geological standpoint, the Canadian part of the continent may very naturally be regarded as composed of two great divisions—an eastern and a western—the line between these beginning at the south near Winnipeg and running thence along the outer edge of the Laurentian plateau north-westward to the Arctic Ocean. To the east of this line, while the surface is generally broken and irregular, the relief is nearly everywhere comparatively low. The rocks are almost altogether referable to the Palaeozoic systems or to systems older than these, and there is little evidence of important changes during the later geological periods beyond such as is incident to the gradual wearing away and denudation of ancient highlands and mountain systems.

To the west the Mesozoic and Tertiary systems become important. The entire spread of the great plains is floored by such rocks, and they occupy also a large part of the western Cordilleran belt, although there mingled with important areas of much older rocks. Many of the mountain ranges of the Cordillera are rugged, new and lofty, and the processes of denudation are still going on very rapidly, with rivers and streams flowing at high grades and very far from that passive condition, where the drainage system has approximately reached the base-level of erosion.

A two-fold division of the northern part of the continent, of the kind above indicated, although based upon fundamental facts, is, however, much too general for the purposes of description of its several regions. The boundaries of the several provinces, resulting from circumstances of a more or less political kind, do not always correspond with the natural features and cannot therefore be adopted as the best for purposes of geographical and geological description. Relying chiefly upon the physical and geological facts, we may therefore further subdivide Canada as follows:—

(1) The Appalachian Region, including the Maritime Provinces of the Atlantic and the south-eastern part of-the Province of Quebec bounded by a line running from the Straits of Belle Isle to the City of Quebec and thence to Lake Champlain.

(2) The Lowlands of the St. Lawrence Valley, extending, with an irregular width, from the City of Quebec to Lake Huron and including the Ontario peninsula.

(3) The Laurentian Plateau.

(4) The Arctic Archipelago.

(5) The Interior Continental Plain, running from the 19th parallel to the Arctic Ocean and including part of Manitoba, Saskatchewan, Alberta and the North-West Territories.

(6) The Cordillera, or great mountain belt of the west, including the greater part of British Columbia and the whole of the Yukon district.

The Appalachian Region of Canada includes the Maritime Provinces of Nova Scotia, New Brunswick and Prince Edward Island and the portion of the province of Quebec lying east of the St. Lawrence River up to the City of Quebec and from there east of a line running south-westerly to Lake Champlain. The region is part of a zone that has been the seat of successive mountain building forces that gave form to the eastern part of the North American continent and yielded the Appalachian mountain system that, commencing not far north of the Gulf of Mexico, runs north-eastward through the Atlantic states and eastern Quebec to the Gulf of St. Lawrence. This mountain system is represented in Vermont and New Hampshire by the Green and White Mountains, and its main line runs on, though with much decreased elevation, through the south-eastern part of the Province of Quebec, under the name of the Notre Dame Mountains. Not far below the City of Quebec it approaches the St. Lawrence, and thence continues parallel with that river and its great estuary, all the way to Gaspe on the open gulf. In the Gaspe peninsula it is known as the Shickshock Mountains. Considerable parts of these mountains rise above 3,000 feet, but the Notre Dame range seldom exceeds 1,000 or 1,500 feet, and its elevations resemble rolling and broken hills and ridges rather than mountains properly so called. The whole length of this main continuation of the Appalachian system in Canada is about 500 miles. " Subordinate and less continuous elevations, nearly parallel to the main ridge thus outlined, occur in New Brunswick, chiefly along two lines, one of which strikes Chaleur Bay below its head, the other, somewhat divergent in direction to the eastward, borders the southern shore of the province along the Bay of Fundy. Though living at some distance to the south, eastward of the main line, the peninsula of Nova Scotia may best be regarded as a member of the Appalachian system of uplifts, with which it is parallel. Its elevation nowhere exceeds 1,200 feet, and is in general very much less. A broad range of broken hills and uplands extends along the Atlantic coast of the province and into the island of Cape Breton.

the general sense in which the term "Appalachian Region" has been employed, it has thus a width of about 350 miles between the outer coasts of Nova Scotia and the St. Lawrence estuary. Followed to the south-westward, this belt of country embraces the New England States and part of New York, all with very similar physical features. In the opposite direction it is interrupted by the Gulf of St. Lawrence, but reappears in the great island of Newfoundland, still preserving most of its characteristic features. Throughout this region, including Newfoundland, the geological structure is very similar, the formations represented are nearly the same, and both in composition and from a palaeontological standpoint they often resemble those of the opposite side of the Atlantic more closely than they do those of other parts of America.

Much of the area comprised in what has been designated the Appalachian Region, in Quebec and New Brunswick, affords excellent arable land or supports valuable forests. The character of the soil varies greatly, chiefly in conformity with that of the subjacent rocks, but it has also been considerably affected, as almost all parts of Canada, by the nature and amount of the deposits due to the glacial period. The best arable lands of Nova Scotia are situated towards the Bay of Fundy and along the northern side of the peninsula generally. The surface of Prince Edward Island is for-the most part fertile and highly cultivated, and nowhere exceeds 500 feet above the level of the sea.

The geological scale is well represented in the Appalachian Region from the pre-Cambrian to the Triassic, but thereafter ensues a long gap, during which no deposits appear to have formed, probably because the area in question then existed as land, exposed to denuding agencies alone. Closing this unrepresented lapse of time, we find only the clays, sands and drift referable to the glacial period.

Though lying eastward of the chief axis of elevated country in Quebec, and no longer mountainous the Maritime Provinces owe their main physical features and geological structure to the same general forces that operated in the case of the more typical mountainous districts in Quebec. The depression of the Bay of Chaleur, the northern highlands of New Brunswick and the hilly country of the same province bordering the Bay of Fundy, this body of water itself and the peninsula of Nova Scotia, all at least roughly parallel the general north-easterly Appalachian trend. These physical features reflect the broader geological structures of the country, whose strata up to and including the Devonian are in general folded along axes following a north-easterly course. But the Carboniferous and overlying Permian strata occupying the low, triangular basin in New Brunswick fronting on the Gulf of St. Lawrence, lie flat and comparatively undisturbed, and with similar attitudes underlie the Province of Prince Edward Island, though in their extension eastward through Nova Scotia into Cape Breton, they frequently occur in a highly disturbed condition.

Rocks of pre-Cambrian age occur along the lines of main uplift in south-eastern and north-eastern Quebec, in the northern and southern highlands of New Brunswick and in Cape Breton. In Quebec, the pre-Cambrian is largely, if not solely, composed of igneous rocks, chiefly basic eruptives and their derivatives; in New Brunswick and Nova Scotia, crystalline limestones, various schistose rocks, possibly of sedimentary origin, and acid and basic, igneous rocks occupy the pre-Cambrian areas.

Forming the backbone of the peninsula of Nova Scotia, and bordering the whole Atlantic coast, is a belt characterized by a group of sediments invaded by large batho-litic bodies of granite, probably of Devonian age. This sedimentary group has yielded a section at least 5,000 feet thick, and has generally been regarded as of Lower Cambrian age, though possibly it should be classed as pre-Cambrian. The group is divisible into a lower quartzite series and an upper argillaceous series. The strata have been thrown into a great series of parallel, sharp flexures with which the distribution of the widespread aurifeous quartz veins is so closely connected.

Undoubted Cambrian strata, often richly fossiliferous, occur in Cape Breton, in the neighborhood of St, John, New Brunswick and in Quebec, where they almost continuously border the St. Lawrence River from the extremity of Gaspe peninsula to Quebec City, continuing thence in a more broken zone to the Vermont border. In all the areas the strata in general are argillaceous or arenaceous, and range in age from the lowest to the highest Cambrian, at times passing upwards, without a break, into the Ordovician. But while the lower beds of the 5,000 to 6,000 foot, Quebec section, are characterized by the presence of the Ollenellus fauna, the corresponding strata of the 2,000 to 3,000 foot section of the Maritime Provinces are distinguished by the occurence of the Holmia fauna.

Ordovician strata occur throughout the eastern part of the Province of Quebec, often infolded with the Cambrian and pre-Cambrian formations. Fossiliferous beds of this age occur in northern New Brunswick, but the system is chiefly represented in this province and in Nova Scotia by areas of highly disturbed, mainly volcanic rocks.

Silurian rocks are widely spread in northern New Brunswick and in the adjacent portions of Quebec, occupying the greater part of this area which drains to the Bay of Chaleur. They recur in the southern part of New Brunswick and in the northern part of Nova Scotia, and though comprising limestones, calcareous shales and sandstones, are often greatly intermixed with' contemporaneous volcanic material.

Devonian strata, only sparingly represented in southeastern Quebec, are extensively developed in Gaspe, where this system has yielded a section of about 9,000 feet, of which the lower 2,000 feet are largely of marine, calcareous strata, while the upper portion is chiefly of sandstone and conglomerates containing a remarkably rich flora. About the head of the Bay of Chaleur rocks of this age have yielded many interesting fish remains, comparing closely with those of the Old Red Sandstone. Somewhat analogous conditions appear to hold elsewhere in the Maritime Provinces, while, at times, the lower part of the Devonian in Nova Scotia is represented by fossiliferous limestones with iron ore.

While during Devonian times a large part of the Appalachian Region appears to have been a basin of deposition, the period was also marked by extensive invasions of plutonic rocks, chiefly granites, in south-eastern Quebec, New Brunswick and Nova Scotia. Towards the close of the Devonian, or in early Carboniferous times, the activities of the mountain building forces in this region seem to have culminated, and over extensive areas the Carboniferous and Permian strata still occur in nearly horizontal beds.

The Carboniferous system, both from its extent and because of its economic value, must be considered as one of the most important features of Nova Scotia and New Brunswick, and there is reason to believe that much larger tracts of this formation still lie beneath the waters of the Gulf of St. Lawrence and the Atlantic. Its total thickness is, in some parts of Nova Scotia, estimated at 16,000 feet, but it is very irregular in this respect and over the greater part of New Brunswick is comparatively thin. At the Joggins, on the north arm of the Bay of Fundy, is a remarkable continuous section showing 14,570 feet of strata, including seventy seams of coal. From beds in this section numerous specimens of a land-inhabiting reptilian fauna have been described. The flora of the period is well represented in many places, particularly in Nova Scotia, and includes that of several distinct stages, beginning with the Horton group at the base (comparable with the “caleiferous sandstone" of Scotland) and at the top containing so many forms referable to the Permian that the name Permo-Carboniferous has been applied to this part of the section Several local unconformities have been determined in different parts of this great succession of beds. With the marine limestones important deposits of gypsum are found. The workable coal seams occur in what is called the Middle Carboniferous, and some of these, in the Pictou district, are of unusual thickness. Coal mining is actively in progress in Cumberland and Pictou counties and in Cape Breton, the total annual output being between six and seven million tons. In New Brunswick the productive area for coal appears to be small, and the seams so far found are of inconsiderable thickness.

Triassic measures occur along the greater part of the Nova Scotia shore of the Bay of Fundy, by dikes and cut sills of diabase or overlain by thick sheets of the same material. Similar, but much less extensive beds, occur on the opposite, New Brunswick, shore. From Triassic times onwards to the Glacial period the Appalachian Region of Canada appears to have been continuously elevated, undergoing denudation, and perhaps during the Cretaceous period the eastern part was peneplanated. Some facts respecting the glacial deposits of the Appalachian Region are given on a later page, with general statements relating to this period in Eastern Canada

To complete this very brief review of the geology of what has been called the Appalachian Region it now only remains to add a few words concerning that main line of uplift and disturbance the course of which was first traced through the Province of Quebec, from the vicinity of Lake Champlain to Gaspe. This structurally complicated belt of country- has been the subject of much controversy, and possesses a literature of its own. It is bounded to the north-westward by an important dislocation or break, known as the St. Lawrence and Champlain fault, which may be traced from Lake Champlain to Quebec City and thence follows the estuary of the St. Lawrence, probably running to the south of Anticosti. To the west of this line are the flat-lying Ordovician strata of the St. Lawrence plain, chiefly limestones, and doubtless resting upon a strong shelf of the Laurentian nucleus at no great depth. Against this stable edge the eastern strata have been folded, faulted and ridged up by the forces which produced the Appalachian range. Were this all, a careful study of the beds on the two sides of the line would readily show their identity; but it appears that previous to the great epoch of disturbance the original physical conditions themselves differed. To the west a sheltered sea came into existence about the close of the Cambrian period, in which Ordovician strata, in large part limestones, were laid down. To the east sedimentation began much earlier, and the circumstances of deposition were different and more varied. Even the animal life present in the two districts was largely dissimilar at the same period. Thus it was not until much study and thought had been given to the problem that Logan was enabled to affirm the equivalency of a great part of the strata on the two sides of the St. Lawrence and Champlain fault. To those on the east, differing in composition and fauna from the rocks of the typical New York section, he applied the name “Quebec Group.” Subsequent investigations have shown, however, that in the ridging up of this part of the Appalachian region not onlv are some very old Cambrian rocks brought to the surface, but considerable areas of crystalline schists, which are evidently pre-Cambrian.

The Appalachian Region in Canada, as in the United States, is productive of minerals. In the eastern townships of Quebec are the celebrated asbestos deposits that furnish 90 per cent, of the world’s supply. Chromite, copper and iron pyrites are also mined in this region. Considerable placer gold has been recovered. In Nova Scotia are some of the principal coal mines of Canada, notably at Sydney, Port Hood, Mabou, Inverness, Chimney Cove, Pictou, Cumberland and Joggins. Gold has been produced for over forty years. Antimony, tin and tungsten are also receiving attention. Iron ore has been mined for many years. Manganese ore occurs in both Nova Scotia-and New Brunswick, sometimes of exceptional purity. Gypsum occurs in large bodies up to 150 feet in thickness, and is extensively worked. Bituminous shales, rich in oil, and ammounium sulphate are found in New Brunswick and Nova Scotia. Whetstones and building material of excellent quality are found in abundance.

Lowlands of the St. Lawrence Valley. The tract of country, which it is found convenient to include under this name, comprises but a small part of the hydrographic basin of the great river, which in all is about 530,000 square miles in extent. Although not altogether un interrupted, it is clearly enough defined in a general way by the edge of the Laurentian plateau on the north, the Appalachian highlands to the south-east, and on the south further west, bv the line of the St. Lawrence River and the lower members of the svstem of the Great Lakes. It may be described as extending from a short distance below the city of Quebec to Lake Huron, with a length of over 600 miles and an area of more than 35,000 square miles, all of which may be regarded as fertile arable land -—the greatest connected area of such land in Eastern Canada.

These lowlands are based upon nearly horizontal strata, ranging in age from the latest Cambrian to the Devonian. On a geological map its limits are readily observable, but in order to understand its character it is necessary to consider it somewhat more closely, and under such scrutiny it is found to break up naturally into three parts. The first of these lies partly in Quebec and partly in Ontario, extending west along the St. Lawrence and its great tributary, the Ottawa, to a north-and-south line drawn about twenty-five miles west of the city of Ottawa, or somewhat past the 76th meridian. It is here interrupted by a projecting, but not bold, spur of the Laurentian plateau, which crosses the St. Lawrence at the lower end of Lake Ontario, forming there the Thousand Islands, and runs southward to join the large pre-Cambrian tract of the Adirondacks in the State of New York. This eastern division, with an area of 11,400 square miles, constitutes what may be called the St. Lawrence plain proper. Much of its surface is almost absolutely level, and it nowhere exceeds a few hundred feet in elevation above the sea, although a few bold igneous hills stand out in an irregular line, with heights of 500 to 1,800 feet. Mount Royal, at Montreal, is one of these, and from it all the others are in sight, while the Laurentian highlands may also be seen thirty miles to the north, and to the southward the Green Mountains and Adirondacks, forming the boundary of the plain in that direction, are apparent on a clear day.

Beyond the projecting spur of ancient crystalline rocks above referred to, from the lower end of Lake Ontario, near Kingston, to Georgian Bay of Lake Huron, the southern edge of the Laurentian plateau runs, in a slightly sinuous line, nearly due west for 200 miles. Between this edge and Lake Ontario on the south lies a second great tract of plain, the lowest parts of which may be considered as level with Lake Ontario (246 feet), but of which no part exceeds 1,000 feet above the sea. This plain is naturally bounded to the south and west by the rather bold escarpment of the Niagara limestone, which, after giving rise to the Falls of Niagara between Lakes Ontario and Erie, runs across this part of the Province of Ontario to Lake Huron, forming there a long projecting point and continuing still further west, in the chain of the Manitoulin Islands. The area of this second tract of plain is about 9,700 square miles. It is scarcely more varied in its surface than that to the eastward, and throughout most of its extent is a fertile farming country.

The third and last subdivision of the lowlands of the St. Lawrence Valley is an area of triangular form, included between the Niagara escarpment and Lakes Erie and Huron. This constitutes what is generally known as the Ontario peninsula, and its south-west extremity touches the 42nd parallel, the latitude of Rome. The area of the Ontario peninsula is 14,200 square miles, and both in soil and climate it is singularly favored. Grapes, peaches and maize are staple crops in many districts. To the north some tracts of this land are high and bold, but most of its surface varies from 500 to 1,000 feet above the sea.

The geological features of the lowlands of the St. Lawrence valley are comparatively simple. The rocks flooring the region lie either horizontally or at very low angles upon the spreading base of the pre-Cambrian mass to the northward, the crystalline rocks of which have frequently been met with in deep borings. The formations represented correspond closely with those of the New York section, and the series, beginning with the Potsdam sandstone, continues upward without any marked break to the Chemung or later Devonian.

In the first or eastern subdivision of this region, the Potsdam sandstone, although strictly speaking referable to the Upper Cambrian, physically considered is really the basal arenaceous and conglomeratic member of the Ordovician series which follows. The several members of the Ordovician occupy almost the entire surface, diversified merely by a few light structural undulations, which in several districts result in the introduction of some higher beds that are referred, although with some doubt, to the Silurian.

Passing to the second or central subdivision, to the west of Kingston all but the lower Ordovician formations, lust referred to, are found to be repeated, in ascending order, along the north shore of Lake Ontario, with very similar characters and equally undisturbed. The Trenton limestone occupies the greatest area, extending in a wide belt to Georgian Bay of Lake Huron. Above this lie the Utica shales, and over these the Hudson River formation. This is the highest member of the Ordovician, but the plain also overlaps the lower members of the succeeding Silurian system irregularly, finding its natural boundary from a physical point of view only at the massive outcrop of the Niagara limestone.

The course of the escarpement produced by this outcrop has already been traced; above it, and to the southwest, lies the higher plain generally known as the Ontario peninsula, constituting the third subdivision of the St. Lawrence lowlands. More than half of the area of this peninsula is occupied by Devonian rocks, which succeed the Silurian regularly in ascending order, the highest beds being met with in the extreme south-west of Ontario, beyond which they are soon followed by the Carboniferous basin of the Michigan peninsula. The Silurian and Devonian strata are affected only by slight and low undulations, but these are important in connection with the exploitation of the oil and gas of the region.

Though not a portion of the Laurentian lowlands, mention may be made at this point of the island of Anticosti, lying in the wide estuary of the St. Lawrence. The island is about 140 miles in length, and consists of nearly flat-lying rocks, chiefly of the Silurian, with some of Ordovician age, (Hudson River) along its northern side. The island evidently represents part of a submerged and undisturbed Ordovician and Silurian tract of the northern part of the Gulf of St. Lawrence, the rocks of which differ in some respects from their representatives further to the west, while in some instances the enclosed fauna find their closest analogy in the fauna of the distant Mani-toulin Islands of Lake Huron. On the mainland, opposite to the island, lower members of the Ordovician occur,

resting on the pre-Cambrian, while further east, towards the Straits of Belle Isle, Cambrian strata repose on the ancient crystalline rocks.

In the two eastern subdivisions of the lowlands of the St. Lawrence valley, with the exception of structural materials, such as stone, lime and clay, minerals of economic value are scarcely found, but the clay and cement industries are becoming highly important; but in the third or westernmost subdivision, however in addition to these, gypsum, salt, petroleum and natural gas have become important products. The gypsum and salt are derived from the Onondaga formation of the Silurian. The salt is obtained in the form of brine from deep wells, but beds of rock-salt are known to occur at consider able depths. Petroleum is chiefly derived from the Corniferous limestone of the Devonian, and natural gas is obtained from several horizons in the Devonian, Silurian and Ordovician.

The Laurentian Plateau. The great region thus named, composed of very ancient crystalline rocks, has an area of over 2,000,000 square miles, or more than one-half that of the entire Dominion of Canada. In a horse-shoelike form, open to the north, it surrounds three sides of the comparatively shallow sea known as Hudson Bav. Its southern part is divided between the Provinces of Quebec and Ontario, its eastern side expanding into the Labrador peninsula, while the western runs, with narrow dimensions, to the Arctic Sea, west of the great bay.

In geographical extent it is thus very important-although somewhat monotonous in its physical and geological features. It contributes little to the fertile areas of the country in proportion to its size, but in the aggregate comprises a considerable amount of land which is either cultivated or susceptible of cultivation. Elsewhere, in its southern parts, it carries forests of great value, and its mineral resources are already known in some places to be very important. It constitutes, moreover, a gathering ground for many large and almost innumerable small rivers and streams, which, in the sources of power they offer in their descent to the lower adjacent levels, are likely to prove, in the near future, of greater and more permanent value to the industries of the country than an extensive coal field. Particularly notable from this point of view is the long series of available water power which runs from the Strait of Belle Isle nearly to the head of Lake Superior, coincident with the southern border of the plateau.

Although it is appropriate to describe this region as a plateau or tableland, such terms, it must be understood, are applicable only in a very general way. Its average elevation of about 1,500 feet is notably greater than that of the adjacent lands, and is maintained with considerable regularity, but its surface is nearly everywhere hummocky or undulating. Away from its borders, the streams draining it are, as a rule, extremely irregular and tortuous, flowing from lake to lake in almost every direction, but assuming more direct and rapid courses in deeply cut valleys as they eventually leave it. Many of the surface features are of very great antiquity, and in Labrador and elsewhere a number of the larger valleys existed much in their present form long before the Cambrian period.

The average height of the central parts of the Labrador peninsula is about 1,700 feet, and the most of its drainage is divided between Hudson Bay, Ungava Bay and the Atlantic coast, the main watershed lying not very far to the north of the St. Lawrence estuary and gulf. Along the Atlantic coast, to the north of Hamilton Inlet, the region assumes a really mountainous character, numerous elevations attaining 3,000 feet and some as much as 5,000 or 6,000 feet. These are the highest known points connected with any part of the Laurentian region, and are quite exceptional in character.

To the south of Hudson Bay the watershed is, at least in one part, as low as 1,000 feet. North of Lake Winnipeg the Nelson and Churchill Rivers cros-s the Laurentian plateau in a wide depression, to reach Hudson Bay. Still further north this part of the plateau has a height of over 1,200 feet above the sea.

Generally speaking, the surface of the plateau is barren and rocky, with wide, swampy tracts, especially towards the height of land. To the south and south-west of Hudson Bay it is overlapped by an important area of Silurian and Devonian rocks, over which, and the adjacent parts of the crystalline rocks, is rather uniformly spread a mantle of boulder clay of two distinct ages, overlain by remnants of marine clay which reach to a height of over 450 feet above the level of the bay. Lacustrine clays, deposited in the basins of glacial lakes, cover large areas, notably north-west of Lake Winnipeg and south of James Bay, where they constitute large tracts of arable land which will eventually be of value.

The striking features of the Laurentian plateau are innumerable lakes, large and small, with intervening rounded rocky elevations, wooded in their natural conditions to the south but rising above the tree line to the northward, while in the far north, on both sides of Hudson Bay, hills and valleys become eventually characterized by grasses, mosses and lichens alone, constituting the great “barren lands” of North America. The rivers and lakes are everywhere well stocked with fish, while deer and moose in the southern parts, and to the north the caribou, abound. Thus, where the region can be entered without undue difficulty, it has already become a much favored resort of the sportsman.

The Laurentian plateau, also known as the Canadian Shield and as Laurentia, is composed of several groups of rocks. As at present known, the oldest consists largely of voloanics, “greenstones,” often schistose, accompanied by some sedimentary schists, limestones and an “iron formation.” This group, found in northern and western Ontario, and known as the Keewatin, rests on intrusive granitic rocks that also occupy large areas over which they are frequently gneissic. Some basic igneous rocks are also found intrusive in these older rocks.

This whole assemblage of prevailingly igneous rocks is characterized by its great metamorphism. It has been subjected to intense disturbances, regional in extent. It formed a land area whose surface was eroded into hill and vale, very much like the present surface of the Laurentian plateau, before the next succeeding, well recognized system of rocks known as the Huronian was laid down. This svstem is largely sedimentary, as the preceding was largely igneous; conglomerates, slates and quartzites are the characteristic rocks of this system. These relationships are best seen in the Lake Superior and Temiskaming regions, but over considerable districts they have been obscured by later intrusions of granitic rocks.

The Huronian as it occurs in the original locality on the north shore of Lake Huron is divisible into two portions, known as the Lower and Middle Huronian. Traced westward into the United States, the Huronian system has been found to be divisible into three portions, of which the upper, the Upper Huronian or Animikie, is typically developed in Canada near Port Arthur on Lake Superior. Younger than the Animikie, a group of sandstones, conglomerates and trap known as the Ke-weenawan or Nipigon system, is well developed near Lake Nipigon, north of Lake Superior. The age of these rocks is generally supposed to be pre-Cambrian, though by some held to be Lower Cambrian.

In eastern Ontario and the adjoining portions of Quebec the pre-Cambrian rocks consist of a distinctly stratified series of limestones and other sedimentary rocks, usually highly altered and crystalline, with a second series of more gneissic intrusive rocks, whose apparent bedding is really a foliation due to pressure and which frequently pass into granites by imperceptible gradations. The first of these is known as the Grenville series, the second has been termed the Fundamental or Ottawa Gneiss.

Sir William Logan, who studied the “Fundamental” (Ottawa) Gneiss, the Grenville series and the Huronian, recognized the great unconformity between the Huronian and the older rocks and the metamorphosed character of the latter as contrasted with the comparatively unaltered, distinctly sedimentary nature of the former. He therefore divided the pre-Palaeozoic rocks into Huronian, which he defined as embracing the pre-Cambrian above this unconformity, and Laurentian, which embraced everything below. .

An international committee on nomenclature, representing Canadian and American geologists, has recommended the following classification of the pre-Cambrian. Opposite is placed a classification based on Logan’s and in general agreement with the use of the terms in the reports of the Canadian Geological Survey, though in reconnaisance work the distinction between Keewatin and Huronian has not always been observed.

In reference to the above table, it may be stated that the Laurentian as defined by the International Committee is restricted to the pre-Huronian granites and gneisses, and that the relationships between Grenville and Keewatin, owing to their geographical distribution, is not yet established.

The greater part of the great Laurentian plateau, following the usage of the Canadian Geological Survey, may be represented as Laurentian, since it is dominantly underlain by granite rocks or their gneissic modifications, Keewatin or the Grenville series as found in their typical localities. But throughout this vast region are many areas, 'often of considerable extent, occupied by Huronian and, possibly, Keweenawan rocks. Both east and west of Hudson Bay rocks similar to the Animikie characterize considerable districts, and in the far north, west of Hudson Bay, are areas of rocks probably referable to the Keweenawan.

Though the region of the Canadian Shield was, during pre-Cambrian time, the scat of repeated widespread disturbances and invasions of plutonic rocks, amongst which the extensive bodies of anorthosite distributed along the south-western border of the region and the varied alkali and nephiline syenites of Eastern Ontario are especially notable, yet, since earliest Palaeozoic times the region does not appear to have been affected by regional disturbances, nor does there appear to have been even local intrusions of igneous rocks.

The rocks of the pre-Cambrian are remarkable for the variety of useful and valuable minerals they contain. Iron, copper, nickel, cobalt, silver, gold, platinum, lead, zinc, arsenic, pyrite, mica, apatite, graphite, molybdenite, feldspar, corundum, talc, actinolite, the rare earths, ornamental stones and gems, building materials, all are found, and most of them are being or have been profitably mined.

In the tongue of these rocks, which in ;the Lake Superior region extends into the United States, are the great iron ranges, which have produced 400 million tons or ore. and which are expected to furnish 1,500 million tons more; and here also are the great Lake Superior copper mines that have produced four and a half billion pounds of copper and are still increasing their annual production. The fringe of the Laurentian plateau that is explored in Canada has also been prolific. Near Sudbury are the greatest nickel mines in the world, and in the Cobalt-Montreal River district what promises to be one of the greatest silver districts. Iron ore formation, which occurs in the Keewatin, Lower and Upper Huronian, occurs in patches throughout the whole extent of Northern Ontario into Quebec. Iron ores are also found in Eastern Ontario and Quebec. Copper is important in the nickel deposits, and is also found in separate deposits. Mica is an important product in Eastern Ontario and Quebec. Some of the deposits are probably unexcelled anywhere. The corrundum deposits of Eastern Ontario are unique. Gold has been mined in Eastern Ontario and in the Lake of the Woods district. Feldspar and pyrite mining is important. In the far north, explorers report occurrences of much the same minerals as known along the southern fringe of the Laurentian plateau.

The Arctic Archipelago. The islands of the Arctic archipelago extend from the north side of Hudson Bay and Hudson Strait for a distance of 1,500 miles, while their greatest extension east and west is along the 73rd parallel, a distance of 500 miles. The total area of these northern islands is well over 500,000 square miles, of which Baffin Island, the largest, occupies about 200,000 square miles.

Though naturally much diversified in their physical aspects, the Arctic Islands are characterized in the east, in Baffin, North Devon and Ellesmere Islands by a general tableland rising to elevations of 2,000 to 3,000 feet, but increasing in the north-eastern part of Baffin Island to 5,000 feet, with hills rising perhaps one or two thousand feet higher, while in the northern part of Ellesmere Islands isolated mountain peaks reach nearly to 5,000 feet. Westward of Ellesmere Island the general elevations of the islands of the Parry and Sverdrup groups lie below 1,000 feet. The large islands lying along the border of the continental land, south of the preceding groups and west of Baffin Island, have general elevations of usually less than 500 feet, though in the westernmost island, Banks Island, the general elevation is above 1,000 feet, while the southern part reached an altitude of 3,000 feet.

The greater part of Baffin Island is occupied by pre-Cambrian rocks resembling those of the Labrador peninsula, which extend on northward through North Devon and Ellesmere Islands. Virtually, the pre-Cambrian rocks of Baffin and the adjoining islands to the west occupy an area which, with the U-shaped Laurerltian plateau, entirely encloses Hudson Bay.

Save in the extreme north, on Ellesmere Island where Cambrian rocks passing up into Ordovician rest on the pre-Cambrian, there is usually a considerable time break in the geological sequence between the ancient crystalline rocks and the earliest Palaeozoic measures, usually of Ordovician age. Parts of the western portion of Baffin Island and of the islands to the west, including Victoria Island, are largely occupied by limestones of Ordovician and Silurian age. Banks Island still further west and the Parry Group to the north, and the islands north of Lancaster Sound, are occupied by Devonian and Car boniferous strata, as well as older formations, while the Sverdrup group is largely of Mesozoic strata. Isolated patches of lignite-bearing Tertiary beds occur on the coast of Baffin Island and elsewhere.

Mention may here be made of the extensive Palaeozoic basin of flat-lying measures bordering the southern shores of Hudson Bay from the north of the Churchill River eastward to the foot of James Bay, a distance of about 800 miles. This relatively narrow basin extends south-westward of James Bay to within 120 miles of Lake Superior: South of James Bay the area is largely occupied by Devonian beds, with an interrupted fringe of Silurian and sometimes Ordovician measures. West’ ward of James Bay the strata are largely Silurian, bordered over considerable areas to the south by Ordovician. Palaeontological evidence suggests a former connection on the one hand with the Palaeozoic basin of the Arctic Islands, and on the other with the ancient inland sea at one time occupying Manitoba. Also, in the Devonian times at least, it seems probable that a Palaeozoic sea stretched southward from James Bay to the region of the Great Lakes.

Glaciation of Eastern Canada. Something may be added here on the events of the glacial period as affecting the eastern part of Canada as a whole, although many points connected with this particular period still remain uncertain and the subject of debate. Like the Scandinavian peninsula, the Laurentian plateau at one stage in the glacial period apparently became the seat of a great confluent ice-sheet, which, when at its maximum, flowed down from it in all directions in general conformity with its main slopes. Climatic conditions and relatively local physical features may have conspired to render the discharge of glacial ice more important in some directions than in others, and it is even possible that at no single time was the whole extent of the plateau equally ice-clad. To this continental ice-sheet the name Laurentian glacier has been given, and as there is reason to believe that at times, probably both at the beginning and near the close of the glacial period, there were two principal subordinate centres of distribution, one to the west, the other to the east of Hudson Bay; to these the names Keewatin and Labradorian glacier have been given.

During the whole of this period the Laurentian plateau was in the main an area of denudation. From it the surface material was carried away in all directions, even to the northward, for there is absolutely no evidence that any “polar ice-sheet” ever trenched upon the continent of North America. The generally bare ice-scored rocky surface of these highlands is evidence of this denudation, while the existence of broken, angular masses of unmoved local debris in the central part of Labrador and in the central area of the Keewatin glacier shows that across these neutral gathering-grounds no ice ever passed.

As to the distance to which the solid glacier-ice came southward from the Laurentian plateau, the evidence with respect to the Labradorian glacier is yet inconclusive. Neither is it certain at how many times or to what extent the glacial period was interrupted by relatively warm epochs, but it may be stated that the flora of at least one of these interglacial epochs, as represented in the vicinity of Toronto, is such as to indicate a climate fully as warm as that at present existing, during which it seems improbable that much, if any, glacier-ice could have persisted on the Latirentian highlands.

These problems cannot be discussed here, but it is certain that towards the decline of the glacial period, the region of the Great Lakes was occupied by a succession of fresh-water basins, presumably impounded by the northward, retreating edge of the continental glacier. The evidence of the former existence of these lakes is furnished by numerous beaches, such as the Iroquois and Algonquin beach; somewhat analogous, high level beaches also exist in the valley of the lower St. Lawrence. As a result, southern Ontario is covered by deposits of till, glacial clays, glacial lake clays, etc.

After the final disappearance of the ice-sheet, the

eastern part of Canada, as a whole, stood at a relatively low level. Without quoting in detail the heights to which the sea is known to have reached at this time in various places, it may be stated that it invaded the St. Lawrence valley as far at least as Lake Ontario. Deposits holding marine shells of sub-arctic type have been found at Montreal to a height of 560 feet, and near Ottawa to a height of 470 feet. As a result of the circumstances noted, the St. Lawrence plain as far west as Ottawa, and nearly to Kingston on Lake Ontario, is deeply covered by deposits due to the glacial period, including boulder-clay, Leda clay, and an overlying Sazicava sand, the two last often full of fossil shells of the period. In the coastal regions of the maritime provinces similar deposits occur, to which the same names have been extended, but to the west, around the Great Lakes, no marine forms have been found.

Before leaving the subject it may be noted that it is doubtful if the Laurentide glacier in the east ever crossed the Gaspe peninsula. In New Brunswick and adjacent parts of the State of Maine, during some part of the glacial period, a separate, small gathering ground of ice existed, which has been called the Appalachian glacier. The Magdalen Islands, in the centre of the Gulf of St. Lawrence, appear never to have been glaciated, and it is at least a matter of doubt whether any ice, except that originating on the peninsula itself, ever passed over Nova Scotia.

The Interior Continental Plain. This is bounded on the west by the Rocky Mountains, running about north north-west, and on the east by the edge of the Laurentian plateau, which, taking a, more westerly direction than the mountains, causes the gradual narrowing of the intervening plain to the north Thus on the 49th parallel, here constituting the southern boundary of Canada, the plain has a width of about 800 miles; but it is reduced to less than 400 miles on the 06th parallel. North of the 62nd parallel it is greatly narrowed, the surface becomes more irregular, and is broken by several narrow mountain ranges paralleling the Rocky Mountains.

The southern part of the great plain is much the most important from an economic point of view, and is also that about which most is known. It includes the wide prairie country of the Canadian west, with a spread of about 193,000 square miles of open grass-land, an area more than twice that of Great Britain. Beyond the North Saskatchewan River the plain becomes essentially a region of forest, with only occasional prairie tracts, such as those of the Peace River valley. By chance, rather than by intention, the boundary line of the 49th parallel, to the west of the Red River, nearly coincides with the low watershed which separates the arid drainage-basin of the Missouri from that of the Saskatchewan and its tributaries, cutting off only 20,000 square miles from the Missouri slope. Another line, nearly coinciding with a second low, transverse watershed, may be drawn on the 54th parallel. The watershed crosses this line several times, but in the main it may be taken as dividing the Saskatchewan system of rivers from those of the Mackenzie and the Churchill. The belt of country comprised between these latitude lines is 350 miles wide, with a total area of about 295,000 square miles.

The whole interior plain slopes eastward or northeastward, from the Rocky Mountains towards the foot of the Laurentian highlands, so that a line drawn from the base of the mountains near the 49th parallel to Lake Winnipeg shows an average descent of over five feet to the mile, fully accounting for the generally rapid courses of the rivers of the region. There are, however, in the area to the south of the 54th parallel two lines of escarpment or more abrupt slope, which serve to divide this part of the plain into three portions, and although such a division is by no means definite, it may usefully be alluded to for purposes of description.

The first or lowest prairiedevel is that of the Red River valley, of which the northern part is occupied by the Winnipeg group of lakes, its average elevation being about 800 feet above the sea, although gradually rising to the southward, along the axis of the valley, till it reaches a height of 960 feet about 200 miles to the south of the International boundary. Its area in Canada is about 55,000 square miles, including the lakes, and to the south of Lake Winnipeg it comprises some 7,000 square miles of prairie land, which to the eye is absolutely flat, although rising uniformly to the east and west of the river. This is the former bed of the glacial “Lake Agassiz,” the sediments of which constitute the richest wheat lands of Manitoba.

The escarpment bounding the plain on the west begins at the south in what is known as “Pembina Mountain," and is continued northward in the Riding, Duck, Porcupine and Pasquia Hills, which overlook Manitoba and Winnipegosis Lakes, constituting the main eastern outcrop of the Cretaceous rocks of the plains. From this escarpment the second prairie-level extends westward to a second and nearly parallel marked rise, which, in general, is known as the Missouri Coteau. The area of this plain is about 105,000 square miles, of which more than half is open prairie. Its average elevation is about 1,600 feet, and its surface is more diversified by undulations and low hills and ridges than that of the last, while the river-valleys are often deeply cut as well as wide. The greater part of the surface is well adapted for agriculture, although in places the scarcity of trees constitutes a disadvantage. The character of the soil is also more varied than that of the lower plain.

The third and highest plain, lying between the last and the base of the Rocky Mountains, may be stated to have an average height of 3,000 feet, with an area, between the parallels of latitude referred to, of about 134,000 square miles, of which by far the greater part is absolutely devoid of forest, its wooded area being confined to its northern and north-western edges, near the North Saskatchewan River or its tributaries. The surface of this plain is still more irregular than that of the last, and it is evident that both before and after the glacial period the denuding forces of rain and rivers have acted upon it longer and more energetically. Table-lands like those of the Cypress Hills and Wood Mountain must be regarded as outlying remnants of an older plain of the Tertiary period, and the slopes and flanks of such outliers show that similar processes of waste are still in operation, adding to the length and depth of the ravines and “coulees,” by which the soft Cretaceous and Tertiary rocks are trenched. The deposits of the glacial period, with which even this high plain is thickly covered, have tended to modify the minor asperities resulting from previous denudation. The soil is generally good, and often excellent, but large tracts to the south and west are sub-arid in character; these, while suited naturally rather for pasturage than for ordinary agriculture, are easily rendered fertile by irrigation, and are also responding to the methods of “dry farming.” Along the base of the Rocky Mountains is a belt of “foot-hills,” forming a peculiar and picturesque region, of which the parallel ridges are due to the differing hardness of the Cretaceous rocks, here thrown into wave-like folds, as though crushed against the resistant mass of the older strata of the mountains Taken as a whole, the central plain of the continent in Canada may be regarded as a great shallow trough, of which, owing doubtless to post-Tertiary differential uplift, the western part of the floor is now higher in actual elevation than its eastern Laurentian rim. But although thus remarkably simple and definite m its ,?rand plan, there are many irregularities in detail. The second prairie-level has, for instance, some elevations on its surface as high as the edge of the third plain, both to the west and east of the valley of the Assiniboine River, -which, again, is abnormally depressed. It is not possible here to do more than characterize its features in a general way.

Ever since an early Palaeozoic time, the area now occupied by the interior plain appears to have remained undisturbed, and to have been affected only by wide movements of subsidence or elevation, which, although doubtless unequal as between its different parts, have not materially affected the regularity of the strata laid down. Upon this portion of the continental platform, in its eastern parts on Lake Winnipeg and its associated lakes, Ordovician, Silurian and Devonian rocks are found outcropping along the stable base of the Laurentian plateau. Following this line of outcrop northward, the Devonian rocks gradually overlap those of older date and rest directly upon the pre-Cambrian. They continue to the Arctic Ocean and there occupy a great part of the Northern Archipelago. To the south of Athabasca Lake they rest, without any apparent angular unconformity, upon sandstones referred to very late pre-Cambrian or possibly Lower Cambrian, giving evidences in the stratigraphical hiatus of prolonged periods during Palaeozoic time in which land as well as water existed in some parts of the area. On the western side of the Great Plains the Palaeozoic strata reappear crumpled and broken in the Rocky Mountains, where the vast crustal movements of the Cordilleran belt found their inland limit.

These rocks consist for the most part, of pale-grey or buff, often magnesian, limestones along the eastern outcrop, and from them has been described an extensive and somewhat peculiar fauna. Some, at least, of the Palaeozoic formations represented probably extend beneath the entire area of the Great Plains, but they are wholly concealed there by later strata of Cretaceous age, consisting chiefly of clay-shales and sandstones, generally but little indurated and flat-lying, or nearly so. The uniformity of the surface features of this country is principally due to that of these deposits, which, although since greatly denuded, have worn down very equally and have apparently never been very long subjected to, waste at a great height above the base-level of erosion. The whole area has in fact been one rather of deposition than of denudation up to a time geologically recent, and has very lately been levelled up still further by 'the superficial deposits due to the glacial period.

The Cretaceous rocks are for the most part distinctly marine, although, beginning with the Dakota sandstones in the south, the tar-cemented sands on the Athabasca and elsewhere in the north-west, and the parallel beds, often of coarse material and in greatly increased volume, of the upturned measures of the Rockies, perhaps indicate river-born detritus won from the elevated western country.

In the eastern part of the plains, the Dakota sandstones are succeeded by the Benton shales, the Niobrara, largely calcareous and foraminiferal in some places, the Pierre shales and, lastly, the Fox Hill sandstones. These beds were probably all deposited in a shallow sea. spreading over the territory underlain by the Dakota measures. But further west in Alberta, during the interval represented by part of the Pierre and possibly the Niobrara, the country, over a wide extent, for a time was in a fluctuating state, so that brackish water and fresh water deposits, the Belly River formation, with beds of lignite, formed, but finally were again succeeded by marine deposits. The Dunvegan series of the Peace River, to the north, similarly characterized, is perhaps somewhat older. The Cretaceous strata in fact change very materially in composition and character toward the Rocky Mountains, and when followed to the north give rise to the necessity for local names and render a precise correlation difficult in the absence of connecting sections over great tracts of level country.

All the Cretaceous strata so far referred to belong to the later stages of that system, but in the foot-hills the earlier Cretaceous is represented by the Kootanie formation, holding coal, and reappearing as in folds in the eastern ranges of the Rocky Mountains. One of these is followed by the valley of the Bow River between Banff and Canmore, and affords both anthracite and bituminous coal.

Overlying the Cretaceous rocks proper, in considerable parts of their extent, particularly in Alberta, are those of the Laramie, which, although perfectly conformable with the marine strata beneath, contain brackish water, and in their upper part entirely fresh water forms of molluscs, together with an extensive flora and numerous beds of lignite-coal or coal. As a whole, this formation may be regarded as a transition from the Cretaceous to the Tertiary, with a blending of organic forms, elsewhere considered as characteristic of one or the other. The lower parts are undoubtedly most nearly related to the Cretaceous, and particularly to the Belly River beds, which were laid down under similar physical conditions at an earlier stage. The remains of Dinosaurian reptiles are still abundant in these. The upper beds, constituting what was originally named the Fort Union group, with its local representatives under different names, is, on the contrary, more nearly allied to the Eocene.

A still later stage in the Tertiary is represented by ' beds of Oligocene, found particularly as an outlier capping the Cypress Hills. These have afforded numerous mammalian bones, referred to the stage of White River beds' of the Western States.

The aggregate thickness of the Cretaceous strata of the plains, so far as known, may in the eastern part be stated as about 2,000 feet; in the west, in northern Alberta, it is about the same, but exceeds 2,500 feet in south-western Alberta, without including the Kootanie series of some 7,000 feet or more. The thickness of the Laramie is also great towards the Rocky Mountains, reaching probably §§700 feet. The Pliocene (with perhaps the latter part of the Miocene) appears to have been a time of erosion only, in the area of the Canadian plains; wide, flat-bottomed valleys were cut out in the foothills, and to the cast of these great tracts of country between the now outstanding plateaux must have been reduced to the extent of 1,000 feet or more in height.

The Interior plateau is pre-eminently an agricultural country; minerals are practically confined to the non-metallic substances. These, however, will give rise to important industries. The most important are the mineral fuels in the form of coals, lignite coals and natural gas, with which the plateau is richly supplied. These are obtained from the Cretaceous and Laramie rocks. , The coal-bearing region of the north-west, between the International Boundary line and the 56th degree of latitude is approximately 65,000 square miles in extent. The Souris River country and the region about Medicine Ilat yield lignite only. In western Alberta excellent lignite coals occur, which are being worked at a number of points. In the foot-hills adjacent to the mountains are many deposits of bituminous coal. Natural gas has been found in great quantity, particularly in the region about Medicine Hat, and also two hundred miles north of Edmonton. There is good evidence of the gas fields having a wide extent throughout this region. Great outcrops of Cretaceous sandstones saturated with tar or maltha occur along the Athabasca River, probably evincing the existence of important petroleum reservoirs. Salt springs occur on the borders of Manitoba Lake and in the Athabasca basin. Gypsum also occurs along the eastern outcrop of the Silurian and Devonian rocks, and on the Peace River. Building stones are found, and clay suitable for brick and certain kinds of pottery. The Devonian limestones will probably prove important for cement-making in the East and North, as the Devona Carboniferous of the Rockies have already begun to be.

The Cordillera. Of this great mountainous region of the Pacific Coast, a length of nearly 1,300 miles, is included by the western part of Canada. Much of this is embraced in the Province of British Columbia, where it has a width of about 400 miles between the Great Plains and the Pacific Ocean. To the north it is continued in the Yukon district to the shores of the Arctic Ocean on one side, and on the other passes across the 141st meridian of west longitude into Alaska. Its strongly marked features result from enormous crustal movements parallel to the edge of the Pacific, by which its strata have at several periods, and along different lines, been crumpled, crushed and faulted. These movements having continued at intervals to times geologically recent, the mountains produced by them still stand high and rugged, with streams flowing rapidly and with great erosive power down steep gradients to the sea.

Although preserving in the main a general northwesterly trend, the orographic features of this region are very complicated in detail. No existing map yet properly represents even the principal physical outlines, and the impression gained by the traveller or explorer may well be one of confusion. Disregarding, however, all minor irregularities, two dominant mountain systems are discovered—the Rocky Mountains proper on the east, and the Coast Range of British Columbia on the west.

The first of these it has been proposed to name, from an orographic point of view, the “Laramide Range,” as it is essentially due to earth movements, occuring about the close of the Laramie period, and rocks of that age are included in its flexures. Although not quite continuous (for there are two echelon-like breaks), this range, beginning two or three degrees of latitude to the south of the 49th parallel, forms the eastern member of the Cordillera all the way to the Arctic Ocean, which it reaches not far to the west of the Mackenzie delta. It is chiefly composed of Palaeozoic rocks, largely limestones, and where it has been closely studied, is found to be affected by series of overthrust faults, parallel to its direction, of which the easternmost separates it from the area of the Cretaceous foot-hills. Here the older rocks have been thrust eastward for several miles over the much newer strata. The structure has as yet been worked out in detail only along the line of the Bow River Pass. In width this range seldom exceeds sixty miles. The heights formerly attributed to some peaks appear to have been exaggerated, but any points in its southern part exceed 11,000 or 12,000 feet.

The Coast Range of British Columbia constitutes the main western border of the Cordillera. Beginning near the estuary of the Fraser River, it runs uninterruptedly northward, with an average width of about 100 miles, for at least 900 miles, when it passes inland beyond the head of Lynn Canal. This range is largely composed of granite and more basic plutonic rocks, with infolded masses of altered Palaeozoic and possibly later strata. It is not, as a rule, so rugged in outline as the last, but its western side, rising from the sea, shows the full value of its elevation there, while its main summits often exceed 8,000 or 9,000 feet. Several rivers rising in the plateau country to the eastward flow completely across this range to the Pacific, where the lower parts of their valleys, as well as those of many streams originating in the mountains themselves, in a submerged state constitute the remarkable system of fiords of British Columbia. Even in the arrangement of the islands adjacent to the

coast, the further extension of these valleys, and of others running with the range, may be traced, the evidence being of great subaerial erosion, when the land previously stood at a higher stage. The cutting out of these deep valleys probably began in Eocene times, but was renewed and greatly increased in the later Pliocene.

Outside the Coast Range, and in a partly submerged condition, lies another range, of which Vancouver Island and the Queen Charlotte Islands are projecting ridges. This stands on the edge of the Continental plateau, with the great depths of the Pacific beyond it. The ro£ks resemble those of the Coast Range, but include also masses of Triassic and Cretaceous strata which have participated in its folding, while horizontal Miocene and Pliocene beds skirt some parts of the shores.

In the inland portion of British Columbia, between the Coast and Rocky Mountain systems above particularly alluded to, are numerous less important mountain ranges which, while preserving a general parallelism m trend, are much less continuous. Thus, in travelling westward by the line of the Canadian Pacific Railway, after descending from the Rocky Mountain summit and crossing the Upper Columbia valley, the Selkirk Range has to be surmounted. Beyond this, the Columbia on its southern return is again crossed, and the Gold Range is traversed by the Eagle Pass before entering the Interior Plateau of British Columbia, which occupies the space remaining between this and the Coast Range. The system of ranges lying immediately to the west of the Rocky Mountains proper, notwithstanding its breaks and irregularities, is capable of approximate definition, and its components have been designated collectively the Gold Ranges. Further north it is represented by the Cariboo Mountains, in the mining district of the same name. The highest known summit of this system is Mount Sir Donald, 10,645 feet, one of the Selkirk Mountains. This mountain system is believed to be the oldest in British Columbia It comprises pre-Cambrian rocks with granites, and <a great thickness of older Palaeozoic beds, much disturbed and altered.

The Interior Plateau region constitutes an important physical feature. Near the International Boundary it is terminated southward by a coalescence of rather irregular mountains, and again, to the northward, it ends about latitude 55° 30’ in another plexus of mountains without wide intervals. Its breadth between the margins of the Gold Ranges and the Coast Range is about 100 miles, and its length is about 500 miles. It is convenient to speak of the country thus defined as a plateau because of its difference, in the large, from the more lofty bordering mountains. Its early Tertiary topography has been greatly modified by volcanic accumulations of the Miocene, and by rivcr-erosion, while it stood at a considerable altitude, in the Pliocene ; but its plateau-like character is not obvious until some height has been gained above the lower valleys, where the eye can range along its level horizon-lines. It is highest to the southward, but most of the great valleys traversing it are less in elevation than 3,000 feet above the sea. To the north, and particularly in the vicinity of the group of large lakes occuring there, its main area is less elevated than 3,000 feet, making its average height about 3,500 feet.

Beyond this plateau to the north, the whole widlh of the Cordillera, very imperfectly explored as yet, appears to be mountainous as far as the 59th parallel of latitude, when the ranges diverge or decline, and in the upper' basin of the Yukon, roiling or nearly flat land, at moderate elevations, again begins to occupy wide intervening tracts.

As a whole, the area of the Cordille in Canada may be describe.1 as forest-clad, but the growth of trees is more luxuriant on the western slopes of each of the Cinmmanl mountain ranges, in correspondence with the greater precipitation occuring on these slopes. This is particularly the case in the coast region and on the seaward side of the Coast Range, where magnificent and dense forests of coniferous trees occupy almost the whole available surface. The Interior Plateau, however, constitutes the southern part of a notably dry belt, and includes wide stretches of open, grass-covered hills and valleys, forming excellent cattle ranges. Further north. . along the same belt, similar open country appears intermittently, but the forest invades the greater part of the region. It is only toward the Arctic coast, in relatively very high latitudes, that the barren Arctic tundra country begins, which, sweeping in wider development to the westward, occupies most of the interior of Alaska.

With certain exceptions the farming land of British Columbia is confined to the valleys and tracts below gM\3,000 feet, by reason of the summer frosts occuring at greater heights. There is, however, a considerable area of such land in the aggregate, with a soil generally of great fertility. In some of the southern valleys of the interior, irrigation is necessary for the growth of crops. Fruit growing is becoming one of the important industries.

The geological structure of the Cordillera is extremely complicated, and it has as yet been studied in detail over limited tracts only. There have been no appropriate terms of comparison for the formation met with, and these it has consequently been necessary to investigate independently by the light of first principle. The difficulty is increased by the abundance of rocks of volcanic origin referable to several distinct periods, resembling those of the Appalachian mountain region, though on a vastly greater scale, and, like them, almost entirely devoid of organic remains. The recognition, early in their investigation, has rendered it possible, however, to understand the main geological features, which at first appeared to present an almost insoluble problem.

The oldest rocks recognized consist of crystalline schists probably of pre-Cambrian age, though possibly intricately associated with highly-altered Palaeozoic strata and metamorphosed igneous material. In the Gold Range and Interior Plateau region they have been distinguished as the Shuswap series. They include rocks lithologically resembling the Laurentian gneisses of the east, together with crystalline limestones, quartzites and gneisses like those of the Grenville series. In the Yukon, where similar rocks arc widely developed, they have been grouped under the name of the Nasina series, held to be at least pre-Ordovician in age.

In the Rocky Mountains, Gold Ranges, and elsewhere is a great thickness of Palaeozoic rocks which, in the Rocky Mountain Range, towards the south, is underlain by a considerable volume of relatively unaltered, pre-Cambrian sediments. Cambrian fossils have been recovered from the lower Palaeozoic beds in the south, where the whole of the Cambrian is represented by highly fossiliferous measures, and again in the far north. West of the Rocky Mountains the Cambrian and, in general, the succeeding Palaeozoic systems, are largely represented by volcanic material. The Ordovician and Silurian, on the evidence in each case of a few characteristic fossils, are known to exist at several points in the Rocky Mountains proper. The Devonian has not been distinctly recognized.

In the Rocky Mountains, the Carboniferous is largely represented, chiefly by massive limestones, and the fossils found in these pass down to a stage which has been characterized as Devono-Carboniferous. No single trace of the flora of the Carboniferous period has yet been discovered in the western regions of Canada. In the Interior Plateau and along the Coast, the Carboniferous insists below of volcanic accumulations and quartzites and above of limestones, some of which are largely foraminiferal.

The Triassic, in the southern part of the Rocky Mountains proper, is represented by red sandstones, the deposits of an interior Mediterranean of the period. To the west and north it becomes a marine formation, with peculiar fossils of the “Alpine Trias” type, but over large areas it consists almost entirely of contemporaneous volcanic accumulations.

The Jurassic occurs in the Queen Charlotte Islands and the Fernie shale, underlying the Kootanie formation in the southern portion of the Rocky Mountains, probably belongs to the same system. Rocks of earlier Cretaceous occur in places in the Rocky Mountains and throughout British Columbia as far as the coast, also northward to the Porcupine River, between latitudes 67° and 68°, in the Yukon District. Newer Cretaceous rocks are developed particularly in Vancouver Island, where they constitute the productive coal measures. In the Crow’s Nest Pass region and elsewhere in the Rocky Mountains, as well as in the Queen Charlotte Islands, the earlier Cretaceous rocks contain abundance of good coal. All the. strata of the Cretaceous period are more or less filted and folded, and are evidently prior in date to the last great organic movements of the Cordillera. Evidences of contemporaneous volcanic action are again abundant in some parts of the extent of the Cretaceous.

Rocks referable to the Laramie or transition period between the Cretaceous and Tertiary, are found in the Yukon District and in the vicinity of the Fraser delta, holding ligrite coals and numerous remains of plants. Beds assigned to the Oligocene and Miocene are also well developed in the southern part of the Interior Plateau of British Columbia, where the latter period has been an epoch of notable volcanic eruptions, producing both effusive and fragmental rocks, but toward the close flooding large tracts wi+h basaltic flows. Traces of similar volcanic activity, of the same date, are found in the Queen Charlotte Islands and in Vancouver Island. The Pliocene was chiefly a time of erosion, but deposits referred to this period are not entirely wanting.

Until the completion of the Canadian Pacific transcontinental railway, the west coast of Canada was a remote region, accessible with difficulty; but long before this coal has been successfully mined in Vancouver Island, and in 1858 and succeeding years the discovery and working of placer gold deposits brought the then isolated colony of British Columbia into considerable prominence. From the time of the quarrel with Spain on the Nootka question, in 1870, little had been heard of the region, which remained unprized and suffered naturally in consequence when the “Oregon” boundary was settled with the United States.

Lode mining may be said to have commenced about fifteen years ago. In 1893 the annual production of minerals in British Columbia had a value of about three and a half million dollars. It now runs in the neighborhood of twenty-five millions. The lead of Canada is obtained from the silver-lead mines of East and "West Kootenay. Gold-copper ores are mined extensively at Rossland, and in the Boundary Creek district are enormous copper-gold deposits of the contact meta-morphic type, which are worked on a gigantic scale. Copper is also found in many other parts of British Columbia, particularly along the Pacific Coast. Lode gold is mined in West Kootenay and the Similkameen.

The Cordilleran belt in Canada is not only rich in gold, silver, copper and lead, but it has enormous resources of coal of excellent quality, ranging from lignites to anthracite, conveniently situated. It is mined extensively in the Crow’s Nest Pass, on Bow River, at Nicola, and on Vancouver Island. The great unprospected areas are known to contain the coal formation, and will no doubt when explored add greatly to the coal resources.

While well opened up along the southern fringe of the province, and to some extent along the coast, and while the main streams have been prospected for placer gold, the great part of the Cordilleran belt in Canada may be said to be as yet untouched and its potential wealth in minerals unknown, though it is certain to become one of the great mining countries.

Glaciation of Western Canada. Like the eastern part of Canada, the western has been largely affected by the events of the glacial period. Most of the superficial deposits can be explained only by reference to this period, and to it also the diversion of many rivers and streams and other important changes are due. It is not yet possible to give a connected account of these events, which will meet with general agreement, but, as in the east, the main facts have already been made sufficiently plain.

At an early time in the glacial period, the Cordillera, standing probably at a relatively high elevation, became covered by a confluent ice-sheet, extending approximately from latitude 48° to latitude 63°, with a total length at its maximum of some 1,200 miles. The form of the surface prevented the ice from discharging in al) directions like that of Greenland, and forced the bulk of the outflow to move south-eastward and north-westward, m conformity with the direction of the ruling mountain ranges, from a central neutral gathering-ground or neve, situated approximately between the 55th and 59th parallels. The southward-moving portion of the great glacier filled the Interior Plateau of British Columbia, whilst its opposite extremity in the mam flowed into the Yukon basin Smaller streams from the main mass undoubtedly crossed the Coast Range by transverse valleys, to reinforce secondary, but large glaciers, which reached the sea to the south and north of Vancouver Island, while others extended through the Bow River valley and similar depressions to the western margin of the Great Plains.

This Cordilleran glacier, as shown by late observations in the western part of the Great Plains, was the first to affect the region, and may perhaps prove to be the first notable ice-cap developed during the glacial period in North America. At a later time it became gradually very much reduced, but subsequently, at least once again extended to dimensions in some places approaching those first held by it. Rock striation and the transport of erratics, show that the southern part of the Cordilleran glacier, when at its maximum, passed uninterruptedly over projecting points between 6,000 and 7,000 feet in height above the sea.

In the area of the Great Plains, as above noted, the first recognized evidences of glacial conditions are those connected with the eastward spread of comparatively limited tongues of glacier-ice from the Rocky Mountains, and the deposit, on the western plains, of boulder-clay and rolled gravels attributed to what it has been proposed to name the Albertan stage. Subsequently at least two more distinct boulder-clays, separated by important interglacial deposits, have been laid down over the whole western part of the Great Plains, ending above in silty, sandy and gravelly beds, with large scattered superficial erratics. In connection doubtless with one of these boulder-clays is the remarkable monument of the glacial period known as the Missouri Coteau (crossed by the Canadian Pacific Railway, west of Parkbeg station). These later boulder-clays differ from those of the Albertan stage in being largely composed of debris of the Laurentian and Huronian rocks and Palaeozoic limestones found in places on the eastern side of the interior continental plain. The direction of transport of these erratics has been from the north-east or north north-east.

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