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or animal remains. Fucoids or sea-weeds, it must be remembered, are the only vegetable matters hitherto discovered amongst the fossilized bodies of our Silurian and Lower Devonian rocks. But if we adopt this view, we must adopt, also, certain other and apparently unwarrantable conclusions. The organic remains of these strata are not more numerous than those of other strata in which not the slightest traces even of petroleum have been found; neither do they present any characters peculiar to themselves and suggestive of oil-forming capabilities. Hence we have to infer the existence in the Devonian seas in which these deposits were laid down, of a vast abundance of soft-bodied animals, or sea-weeds, of a nature altogether unknown: & most gratuitous supposition. The enormous quantity of petroleum yielded by these sources, and by others in the American States and elsewhere, renders the formation of this substance from sea weeds or perishable animal remains in the highest degree improbable.

But are we absolutely driven to the adoption of either of the above views, in order to explain the occurrence of petroleum in our Devonian strata? The question mainly turns upon this: Are we forced to assume with certain chemico-geologists-who refuse all explanations of natural phenomena incapable of being rendered evident by labora tory experiments-that all forms of carbon, and all compounds into which carbon enters (with the sole exception of carbonic acid, and that only in part) are necessarily of organic derivation? With all respect for laboratory investigations, some of which have shed much light on obscure geological problems, it cannot be doubted that this view assumes too much. There are many facts, universally recognized as such, which chemistry is quite unable to explain. The allotropic conditions of certain simple bodies, for instance, carbon amongst the number; the existence of chlorine, oxygen, &c., in the solid state in the greater number of their compounds; the peculiar condition of water in hydrated substances, and so forth. We have the positive fact likewise that carbon exists, as such, in meteoric stones; that it separates often in crystalline scales from molten iron; and that it is present in steel, a fusion-product, also, as sometimes prepared. Why, then, are we debarred from assuming its existence amongst the primary or original components of the earth-mass? During volcanic outbreaks in many parts of the world, petroleum has frequently made its appearance, through fissures on the sea-bed, or around the volcanic vent, as one of the products of the eruption. This was memorably the case

in the eruption of Vesuvius in 1861.* The great petroleum springs of Central Asia, which have been flowing for ages also, with those of Zante (mentioned by Herodotus) and others of different localities, lie essentially in areas of volcanic action; and the so-called mud-volcanoes often pour out large quantities of bituminous matter, mixed with other products. It might be argued that in these cases, the petroleum is derived from deeply-seated coal beds, but of this we have no proof. And when we consider the fact that small quantities of bitumen and petroleum occur in rocks geologically far older than those of the coal series, we have an equal right to assume that these matters may be generated, without the aid of organic bodies, by unknown chemical action within the crust of the earth, and may be poured out through fissures from time to time, both amongst deposits under process of accumulation, and amongst others already consolidated. In this manner, I imagine, our petroleum springs of Western Canada have originated. And I would go beyond this, and refer to the same action a leading part in the formation of all bituminous shales, and of coal seams generally. In the latter case, the liquid bitumen or petroleum may be conceived to have flowed into broad marshes, or over low-lying districts, in which an abundant vegetation was under growth. The vegetable matters thus saturated and mixed up with the thickening petroleum, would add their substance to the formation of the coal, and would be chiefly instrumental perhaps in imparting to this its peculiar character. On this view, the formation of bituminous shales by the saturation of the finer kinds of sedimentary matter by petroleum overflows, becomes readily explained; and also the close agreement in character which exists between the shales of the coal measures and those of many Silurian strata. The old view does not explain these points in a satisfactory manner. The petroleum theory likewise obviates the necessity of assuming the growth of an enormous and unparalleled vegetation during the Carboniferous period; and it explains why the vegetation of after periods so rarely yielded. coal-the outflows of petroleum having chiefly taken place during the Carboniferous epoch, and only locally at other times.

The Portage and Chemung Group.-The rocks of this group, so largely developed in the peninsula of Michigan and other districts of

⚫See Canadian Journal, vol. vii, p. 126.

+ If the term "unknown chemical action" be here objected to, we may refer, amongst other cases, to that of the diamond: a substance certainly formed by chemical action, but of a kind altogether unknown to us.

the American States, occur with us in the form only of a few isolated and inconsiderable patches. These consist of black and highly bituminous shales-the probable equivalents of the "Genesee slates," referred by some observers, as already explained, to the Hamilton formation. The principal locality of these shales is Cape Ipperwash, or Kettle Point, in the township of Bosanquet on Lake Huron; but they occur also nearly twenty miles inland from this point, on a creek near Kingston Mills in the south part of the township of Warwick; and also, still further inland, in the township of Brooke. The shales weather dull-grey, and those of Cape Ipperwash are occasionally coated with a yellow crust of oxalate of iron (see PART II. under "Humboldtine"). They contain large spherical concretions (with radiated internal structure) of carbonate of lime; and also much iron pyrites. In the shales of Kettle Point, likewise, long flattened stems of vegetable forms (mostly referred to the Calamites inornatus of Dawson) are of common occurrence; and impressions of fish scales are met with in those of Warwick. The thickness of the exposure at Kettle Point is under fifteen feet; and it is still less than this at the other localities.

Carboniferous Strata.-The Bonaventure Formation.-The only locality at which Carboniferous strata occur in Canada is the southeastern extremity of Gaspé. Exposures of great thickness range along the Bay of Chaleurs and the coast of Percé, and enter Gaspé Bay. These Carboniferous strata occur consequently, for the greater part, in the district of Bonaventure; and as they make up the entire portion of the island of that name, off Percé, Sir William Logan has bestowed upon them the name of the Bonaventure Formation. They consist essentially of conglomerates, associated with red and brown sandstones and some reddish shales. The conglomerates are made up of pebbles of limestone, sandstone, syenite, agate, quartz, and other rock-matters, held together by an arenaceous or partly calcareous cement. Many impressions and casts of vegetable remains occur throughout this formation, but its beds are apparently destitute of coal. They belong to the base of the coal series, proper; and evidently form a portion of the northern rim of the New Brunswick coal field.

The Bonaventure Formation rests unconformably on the Gaspé sandstones and limestones, and dips generally towards the south-east. According to Sir William Logan, it presents a total thickness of about 300 feet.

Fig. 249.

SKETCH-MAP OF THE GEOLOGICAL FORMATIONS OF WESTERN CANADA.

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References to Map on preceding page.

DEVONIAN SERIES:

No. 18. Portage and Chemung Group, (Kettle Point Form.) 17. Hamilton (or Lambton) Formation.

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14. Eurypterus Formation, or Lower Helderberg Group. 13. Onondaga or Gypsiferous Formation.

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9. Medina Formation.

LOWER SILURIAN SERIES:

8. Hudson River Formation.

7. Utica Formation.

6. Trenton (including Bird's Eye and Black River) Fa.

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