detritus thus swept from the earliest lands into the most ancient seas, we view the commencement of that enormous series of derivative strata which, by long-continued repetition of similar processes, have been accumulated to a thickness of many miles.[1]
- ↑ Mr. Conybeare (in his admirable Report on Geology to the British Association for the advancement of Science, 1832, p. 367) shows, that many of the most important principles of the igneous theory, which has been almost demonstrated by modern discoveries, had been anticipated by the universal Leibnitz. "In the fourth section of his Protogæa, Leibnitz presents us with a masterly sketch of his general views, and, perhaps, even in the present day, it would be difficult to lay down more clearly the fundamental positions which must be necessarily common to every theory, attributing geological phenomena in great measure to central igneous agency. He attributes the primary and fundamental rocks to the refrigeration of the crust of this volcanic nucleus; an assumption which well accords with the now almost universally admitted igneous origin of the fundamental granite, and with the structure of the primitive slates, for the insensible gradation of these formations appears to prove that gneiss must have undergone in a greater, and mica slate in a less degree the same action of which the maximum intensity produced granite.
"The dislocations and deranged position of the strata he attributes to the breaking in of vast vaults, ~which the vesicular and cavernous structure assumed by masses, during their refrigeration from a state of fusion must necessarily have occasioned in the crust, thus cooling down and consolidated. He assigns the weight of the materials and the eruption of elastic vapours as the concurrent causes of these disruptions; to which we should perhaps add, that the oscillations of the surface of the still fluid nucleus may, independently of any such cavities, have readily shattered into fragments the refrigerated portion of the crust a especially, as at this early period, it must have been necessarily very thin, and resembling chiefly the scoriæ floating on a surface of lava just beginning to cool. He justly adds, that these disruptions of the crust must, from the disturbances communicated to the incumbent waters, have been necessarily attended with diluvial action on the largest scale. When these waters had subsequently, in the intervals of quiesce nee between these convulsions, deposited the materials first acquired by their force of attrition, these sediments formed, by their consolidation, various stony and earthy strata. Thus, he observes, we may recognise a double origin of the rocky masses, the one by refrigeration from igneous fusion, (which,
