and silver, tin, copper, lead and zinc; in another series, we find beds of coal; in others salt and gypsum; many are composed of freestone, fit for the purpose of architecture; or of limestone, useful both for building and cement; others of clay, convertible by fire into materials of building, and pottery: in almost all we find that most important of mineral productions, iron.
Again, if we look to the great phenomena of physical geography, the grand distributions of the solids of the globe; the disposition of continents and islands above and, amidst the waters; the depth and extent of seas, and lakes, and rivers; the elevation of hills and mountains; the extension of plains; and the excavation, depression, and fractures of valleys; we find them all originating in causes which it is the province of Geology to investigate.
A more minute examination traces the progress of the mineral materials of the earth, through various stages of change and revolution, affecting the strata which compose its surface; and discloses a regular order in the superposition of these strata; recurring at distant intervals, and accompanied by a corresponding regularity in the order of succession of many extinct races of animals and vegetables, that have followed one after another during the progress of these mineral formations; arrangements like these could not have originated in chance, since they afford evidence of law and method in the disposition of mineral matter; and still stronger evidence of design in the structure of the organic remains with which the strata are interspersed.
How then has it happened that a science thus important, comprehending no less than the entire physical history of our planet, and whose documents are co-extensive with the globe, should have been so little regarded, and almost without a name, until the commencement of the present century?
Attempts have been made at various periods, both by practical observers and by ingenious speculators, to establish
