to the fracture, rolling, or abrasure of the crystals, of which they originally formed a part.

"Take for example the very common rock sandstone; its component grains of quartz, felspar, and mica, are more or less rolled or fragmented crystals of these substances, derived from rocks like gneiss, mica, schist, &c., which are also composed of grains of the same kinds, less affected by mechanical processes; or from granite, porphyry, &c., which are purely crystalline rocks. Such derivative sandstones are formed at this day from such crystallized granite and other rocks."-Phillips's Geology, vol. i. p. 31.

"In a general sense, the red sandstone must be considered as formed of fragments, more or less minute, of preceding rocks or minerals. When these are of the usual size of sand, the finer sandstones are produced; when larger, the results are coarser gritstones and conglomerates, or breccias. The term sandstone is, however, equally applied to the whole, although rather in a geological than in a mineralogical sense."-Macculloch's G. C. of Rocks, p. 402.

In the first place, however, this transformation from crystals to grains is not demonstrated. The mere fact that the particles of sandstone consist of the same elements as the quartz crystals of granite, is no proof that they were derived from that rock, any more than the fact that the elements of granite are essentially the same as gneiss and the primary shales and sandstones is proof that that rock was

according to the hypothesis proposed by Sir C. Lyell -formed from them. Yet the theory has no other ground for its support than the mere similarity of their elements.

In the next place, it is inexplicable, on the supposition that they had their origin in granite, that no traces remain in them of the crystals from which they were drawn. Crystallized quartz, even in the state in which it usually exists in granite, is an extremely hard, and under the action of the chemical and mechanical agents to which it is ordinarily exposed, almost indestructible mineral. That vast mountains, that whole continents towering several miles into the atmosphere, and consisting largely of that element, should have been dissolved and reduced in a great measure to the most comminuted particles by the mere chemical and mechanical forces that are now acting on the surface of the globe, may justly be pronounced a physical impossibility. No effect can be conceived more obviously and absolutely beyond the powers of those agents.

No mode of the production of such a change can be suggested that does not leave the theory embarrassed with this insuperable objection. To suppose the quartz and other crystals in granite to have been subjected to a chemical solution, were first to assume that there were chemical forces then in activity of immeasurably greater energy, and operating on a far

wider area, than there now are on the globe. But that is prohibited by the maxims of geology, which require that if the solution of granite mountains and continents is to be accounted for, it should be by forces the same in kind and intensity as those that are now exerting their powers on the earth. Next, if they are supposed to have undergone a solution, then their assumption of their present granular form must have been the effect of a different and peculiar chemical agency. But that is again forbidden by the principles of geology. As no chemical agents are now in activity that generate such silicious grains and aggregations of grains as those that constitute the Potsdam, Calciferous, Medina, and other sandstones, it cannot, according to the maxims of the science, be assumed that they existed and acted at a former period.

The supposition that they were reduced from crystals to their present granular forms-spherical, irregularly rounded, and angular-by mechanical forces, abrading or fracturing them, is embarrassed by equally formidable difficulties. It is altogether incredible that any mechanical force-as of the waves of the ocean, or the current of rivers-should have acted on every point of vast mountains and continents so as to have broken, worn, and disintegrated their whole mass. It is equally incredible that such agents, acting wherever they might, should

have reduced the silicious elements universally of the masses with which they came in contact, to grains of such a minute and uniform size. No result can be conceived more wholly without the limits of possibility than that such causes acting with indefinitely varying forces on rocks differing widely in their solidity, should give birth to such extraordinary effects, and in such unvarying uniformity. No such results spring from their present action. The supposition is, therefore, as absolutely prohibited as the others, by the principles of geology.

We might extend this argument to arenaceous shales, granular quartz, the conglomerates of which silicious pebbles are a principal element, and ordinary sand and gravel. Instead of crystals, they are aggregates of grains, or concretions of minute particles by a law wholly unlike that of geometric crystallization. The theory thus fails as entirely to account for these vast formations as for those that consist of ingredients wholly unlike those of granite. These considerations thus furnish the most resistless demonstration of its error. Whatever else may be thought to have been susceptible of derivation from such continents of granite, the vast beds of gravel, sand, salt, chalk, limestone, and sandstone, cannot have been drawn from that source. Their nature, or the forms in which they exist, make the supposition a paradox. The most indisputable proofs are graven on their fronts that that was not their

origin. But withdrawing these, there is nothing left through the whole mass of the fossiliferous rockseven granting that all the other insuperable obstacles to the theory could be overcome-which its advocates can refer to those fabulous continents, except certain conglomerates and those shales and clays of which alumine is a chief ingredient; a slender basis truly, could they verify their hypothesis in respect to them, on which to erect a demonstration of the immeasurable age of the world! Can a more unfortunate predicament be imagined of writers who have indulged so confident a persuasion that they had established their system by evidence scarcely inferior in certainty to that of mathematics?

Passing over, however, all these insurmountable objections to their theory, let us suppose their imagined continents reduced in any requisite measure to disintegration, transformed into sand, gravel, and pebbles, and traversed by streams and rivers of sufficient size and force to bear such materials to the sea; and there still would be no agent by which they could be spread out on the bottom of the deep over the vast spaces that are occupied by many of the strata. The larger streams, like the Ganges, Indus, Nile, Niger, Amazon, Mississippi, and St. Lawrence, would carry no gravel or sand whatever to the ocean. These great rivers deposit all the heavier particles with which they are charged, in their first stages, hundreds