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stone—we should incline to the belief that the lower shaly deposit was the product of a mud volcano, rapidly ejected and spread over the surface, rendering the sea turbid and discolored to such a degree as to prevent the existence of any organic forms. Afterwards the cessation of the volcanic action allowed the deposition of the grey quartzose mass ; the materials having perhaps the same origin as the grey sandstone which was formed previous to the commencement of the Medina. Although at this period there was no matter ejected from the volcano, still it may have produced oscillations of the surface, causing alternate deep and shallow water, or deep water in some places and shallow in others. Subsequently, towards the close of the grey deposit, the volcano broke forth again with renewed energy, destroying all the organic forms which had come into existence during this comparatively quiescent period, and overwhelming the whole with another deposit of mud like that below. Again, after a time the subterranean action appears to have become more quiet, gradually subsiding, and allowing an increase of sandy matter from some other source. Lastly, towards the termination of the deposit of mud, and when the sand had increased considerably, we find an abundance of vegetable forms, . . . and the whole series terminating with the grey division, marked by that singular fossil, the Dictuolites."—/. Hall's Geology of Western New York, p. 40.

We have the most decisive evidences, therefore, that the great agents that have acted in the depths of the earth where the substances of which the strata consist were originally deposited, were abundantly adequate to transfer them to the surface in the state that was requisite to their conversion into the rocks into which they were formed.

QUESTIONS.

What is the third fact which shows that the strata may have been derived from the interior of the earth? What proofs are there of it? Was the force by which the mountains were upheaved far greater than was requisite to eject a current of lava or other liquid matter from the deep recesses of the earth? Is the force, however, exerted in volcanic eruptions sometimes very great? Give an example of it in Iceland. Give an example in Hawaii. Were the materials of the strata however lavas? What was their state, probably, when ejected into the ocean? Have the crystalline, as well as other rocks, been formed since the creation? What was the form, probably, of the earthy matter which originally constituted the exterior of the globe? Would the water of the ocean, resting on such a bottom, naturally descend in it to a great depth? If in descending ten, fifteen, or twenty miles—the supposed depth of the present volcanic fires—it came in contact with extensive depositories of iron and sulphur, would it not have excited them to a chemical action that would have decomposed it, developed intense heat, generated vast volumes of gas, and thereby caused an upheaval of the soft and pliant mass of earthy matter above; and at length, by forcing passages to the surface, driven it in torrents and rivers into the ocean? Would that part of the surface that was upheaved be acted on also by the waves and currents, and its matter swept off and spread over the bottom of the surrounding sea? Have views like these of the sources from which the matter of the strata was drawn, sometimes been presented by geologists? What is the intimation which Mr. Bakewell presents in respect to it? What are Mr. Featherstonhaugh's suggestions respecting the source from which the treasures of lime were drawn that form the immense beds of that mineral? What other writers have presented similar views T Are there ample proofs, then, that the great agents that have acted in the interior of the earth have been of adequate strength to force the substances to the surface of which the strata aro constructed?

CHAPTER XV.

The Materials of the Strata—Derived from the Interior of the Earth.

These agents were adequate to the transference of the materials of the strata from the interior to the surface, in the period that is represented in the Mosaic record as having intervened betwixt the creation of the earth and the remodification of its surface at the flood. Sixteen hundred, eighteen hundred, or two thousand years were as ample for the work, as sixteen or eighteen thousand, or the immeasurable round of ages which geologists represent as having been occupied in the derivation of the materials of the strata from granitic mountains and continents that were to be disintegrated and transported to the ocean by the feeble agents that are now reducing the rocks to dust, and conveying their detritus to the sea. That the materials for such a process were deposited in the depths of the earth throughout its whole circuit, is seen from the fact, that the whole mass of the granite which is now elevated into the atmosphere, and which lies beneath the stratified formations, has, in the judgment generally of geologists, been raised to fusion by heat from beneath, and received its present crystalline form since the deposition of the primary strata. There is no reason to suppose that a particle of that rock was brought into existence in its present state by the creative fiat. It is the work of powerful chemical and mechanical forces that have since acted on the silex, alumine, potash, soda, lime, iron, magnesia, and other ingredients of which it is constructed. But if that took place in the manner we have supposed, by the evolution of heat in the depths of the earth, the first effect of which was the propulsion to the surface of vast masses of silex, alumine, lime, potash, soda, magnesia, iron, and other elements that enter into the composition of the strata, in the form of minute particles, moistened or rendered liquid by water, then, manifestly, the causes of the propulsion of these materials to the exterior existed beneath every point of the surface, and were as universal as the strata themselves are that have been formed from them. They were undoubtedly, therefore, at least as adetpiate to the production of the latter effect as they were of the former. Indeed, if the views we have presented of the process are correct, the fusion of the granitic elements, which originally lay at the surface, could not have been produced by the evolution of heat in the abysses beneath, without first producing chasms and vents at innumerable points, and forcing up into the superincumbent oceans immense volumes

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