THE FORMATION AND ORIGIN OF COAL.
the preceding chapter we presented the Appalachian basin as it existed at the commencement of the Carboniferous era, when the violent volcanic action of that portion of our continent had ceased or become intermittent, and the great depths of the ancient sea had been filled with the early Palceozoic rocks, leaving but a shallow sea and a soft, low shore for the base of the new and wonderful formations which had now com menced. But, though the violence of eruptive volcanoes could not now pour the molten lava over the new shores, volcanic action and internal heat still had much to do with the subsequent formations.
It was yet early in the creative periods. The "third day," as described by the Mosaic account, had not yet closed, and air-breathing animal life had yet no existence. The air was full of vapor and the floating dust of distant eruptions; carbonic acid loaded the waters and surcharged the air; a sulphurous and heated atmosphere everywhere encircled the earth; and the waters were tepid with the radiating heat of cooling lava and the con densing earth.
The temperature that then existed would be insupportable to terrestrial animals, while the carbonic acid that impregnated the air would be destruc tive to common air-breathing creatures. The vapors of carbon still arose from a thousand sources,—smoking volcanoes and smouldering lava; and every crack and fissure of the earth still poured forth its volumes of the vapors of combustion, which here, in the contact with water, formed car buretted hydrogen, and there, with the atmosphere, formed carbonic acid.
Such a coincidence of favorable circumstances could not fail to produce a vegetation of the most vast and magnificent description, in comparison with which the most luxuriant of the present day would be as a " drop in the bucket." The soft and fertile soil, made rich with the decaying matter of the ancient marine life and the resulting bitumen of the carburetted hydrogen gases; the atmosphere, warm and moist with heat and steam, and loaded with the life-giving carbon so necessary to vegetation, all tended to invigorate and give an unlimited growth to that early flora.
This was the acme of vegetable life. Hitherto those favorable circum stances did not exist, and vegetation could only have flourished to a limited extent.
During the subcarboniferous era, which followed the "old red," or the vespertine, we have noticed an uncertain and meagre coal flora, but in only one instance, in a limited area, was a coal of commercial value produced in this country.* Yet the time that transpired from the vespertine, or proto-carboniferous, to the true carboniferous, was comparatively limited; the red shale, or carboniferous lime, and the conglomerate formations, only intervene.
In tracing the production of the ancient or fossil flora to a later date than the Carboniferous, we also find a great depreciation; and though occa sionally limited fields and thick coal-beds were formed, they are generally both limited in area and in thickness of bed.
Having thus carefully traced the processes of Nature to this remarkable and wonderful period of the earth's existence, we are now, in a measure, prepared to appreciate and comprehend that which is to follow; though we shall still be theorists, notwithstanding the facts, for we get, after all, but dim and uncertain glances into the arcana of Nature. But we have the satisfaction of knowing that our theories are plausible, probable, and con sistent with existing facts and evidences, and that neither miracle nor unnatural processes are required to prove the hypothesis.