It seems certain that the whole of Canada has been violently convulsed by some effort of nature since the floods of the deluge passed away; the mountains are abrupt and irregular in outline, and in some places cleft with immense chasms; the rivers also show singular contortions. North of Quebec and in St. Paul's Bay are many traces of volcanic eruptions, and vast masses of alluvial rocks, bearing marks of vitrification, frequently appear on the surface of the earth. There is, besides, strong evidence that the American Continent has lain for unknown ages beneath the great deep, or that it is of later formation than Europe or Asia.
As far as it has been explored, the general geological structure of Canada exhibits a granite country, with some calcareous rocks of a soft texture in horizontal strata. The lower islands in the St. Lawrence are merely inequalities of the vast granite strata which occasionally stand above the level of the waters; the whole neighboring country appears as if the Great River had at one time covered it. The banks of the St. Lawrence are in many places formed of a schistus substance in a decaying state, but still granite is every where found in strata, inclined, but never parallel to the horizon. In the Gaspé District, many beautiful quartz, and a great variety of cornelians, agates, copals, and jaspers have been found, and traces of coal have also been observed.[152]
The north shore of the St. Lawrence, from thirty miles below Quebec eastward, and along the coast of Labrador, is generally of the primitive formations. Except in the marshes and swamps, rocks obtrude upon the surface in all quarters; in many places, deep fissures of from six inches to two feet wide are seen bearing witness to volcanic violence; the Indians describe some of these rents as several miles long, and forty or fifty deep; when covered with the thick underwood, they are, at times, very dangerous to the traveler. These chasms are probably owing to some great subterranean action; there is a manuscript in the Jesuits' College at Quebec which records the occurrence of an earthquake on the 5th of February, 1663, at about half past 5 P.m., felt through the whole extent of Canada: trees in the forests were torn up and dashed against each other with inconceivable violence; mountains were raised from their foundations and thrown into valleys, leaving awful chasms behind; from the openings issued dense clouds of smoke, dust, and sand; many rivers disappeared, others were diverted from their course, and the great St. Lawrence became suddenly white as far down as the mouth of the Saguenay. The first shock lasted for more than half an hour, but the greatest violence was only for fifteen minutes. At Tadoussac, a shower of volcanic ashes descended upon the rivers, agitating the waters like a tempest. This tremendous earthquake extended simultaneously over 180,000 square miles of country, and lasted for nearly six months almost without intermission.[153]
In the neighborhood of Quebec, a dark clay slate generally appears, and forms the bed of the St. Lawrence as far as Lake Ontario, and even at Niagara; bowlders and other large masses of rock, however, of various kinds, occur in detached portions at many different places. The great elevated ridge of broken country running toward the Ottawa River, at the distance of from fifty to one hundred miles from the north shore of Lake Ontario, and the course of the St. Lawrence, is rich in silver, lead, copper, and iron. On the north shore of the Saguenay, the rugged mountains abound in iron to such an extent as to influence the mariner's compass. The iron mines of St. Maurice[154] have been long known, and found abundantly productive of an admirable metal, inferior to none in the world; it is remarkably pliant and malleable, and little subject to oxydation. In 1667, Colbert sent M. de la Potardière, an experienced mineralogist, to examine these mines; he reported the iron very abundant, and of excellent quality, but it was not till 1737 that the forges were established by the French: they failed to pay the expenses of the speculation; the superintendent and fourteen clerks, however, gained fortunes by the losses of their employers.
There is no doubt that immense mineral resources remain undiscovered among the rocky solitudes of Lower Canada. Marble of excellent quality, and endless variety of color, is found in different parts of the country, and limestone is almost universal. Labrador produces a beautiful and well-known spar of rich and brilliant tints, ultra-marine, greenish yellow, red, and some of a fine pearly gray.
In Upper Canada, the country north of Lake Ontario is generally characterized by a limestone subsoil resting on granite. The rocks about Kingston are usually a very compact limestone, of a bluish-gray color, having a slight silicious admixture, increasing as the depth increases, with occasional intrusions of quartz or hornstone. The limestone strata are horizontal, with the greatest dip when nearest to the elder rock on which it rests; their thickness, like the depths of the soil, varies from a few feet to a few inches: in these formations many minerals are observed; genuine granite is seldom or never found.
West of Lake Ontario, the chasm at the Falls of Niagara shows the strata of the country to be limestone, next slate, and lowest sandstone. Limestone and sandstone compose the secondary formations of a large portion of Canada, and of nearly all that vast extent of country in the United States drained by the Mississippi. At Niagara the interposing structure of slate is nearly forty feet thick, and fragile, like shale crumbling away from under the limestone, thus strengthening the opinion that there has been for many ages a continual retrocession of the Great Falls. Around Lake St. Clair, masses of granite, mica slate, and quartz are found in abundance. The level shores of Lake Huron offer little geological variety; secondary limestone, filled with the usual reliquiæ, is the general structure of the coast, but detached blocks of granite and other primitive rocks are occasionally found: this district appears poor in minerals. The waters of Lakes Huron, Michigan, and Superior have evidently, at some remote period, formed one vast sheet, which probably burst its bounds by a sudden action of nature, and subsided into the present divisions, all lower than the former general level: the separating ridges of these waters are but slightly elevated; great masses of rock and huge bowlders of granite are found rolled at least 100 miles from their original situations, and immense alluvial beds of fresh-water shells, apparently formed since the deluge, but when the waters were still of a vast depth and extent, are found in the east of Lake Huron.
Little or nothing is known of the dreary solitudes beyond Lake Superior; enormous muddy ponds and marshes are succeeded by open, dry, sandy plains; then forests of hemlock and spruce arise, again swamp, bog, windfalls, and stagnant water succeed; in the course of many miles there may not be one dry spot found for a resting-place. The cold is intense in this desolate region; in winter spirits freeze into a consistency like honey; and even in the height of summer the thermometer only shows thirty-six degrees at sunrise. Part of the north and east shore of this greatest of the lakes present old formations—sienite, stratified greenstone, more or less chloritic, and alternating five times with vast beds of granite—the general direction east, with a north or perpendicular dip. Great quantities of the older shell limestone are found strewn in rolled masses on the beach. Amygdaloid occupies also a very large tract to the north, mingled with porphyries, conglomerates, and various other substances. From Thunder Mountain westward, trappose greenstone is the prevailing rock: it gives rise to some strange pilastered precipices near Fort William. Copper[155] abounds in this region to an extent, perhaps, unsurpassed