the waste and spoils of the period. The changes now going on, and the rate of increment of the land above sea-level, the occasional appearance and disappearance of an island, the slow but constant action of the waves upon the coast, and the detrital matter borne down by the rivers, can be no measure of the effects of forces and agencies such as were then in operation. The Mississippi, within a quarter of a century, it has been ascertained, brings down little more than a half of its former spoils. The organic remains, accordingly, which have survived the silurian period, belong chiefly to the molluscous classes, and thin filmy fucoid vegetables; the structures, in short, which were best calculated to live during the period in question, and to remain undestroyed throughout its agitations. The old red sandstone series is likewise of vast extent, both in depth and superficial area. The scale of its mass corresponds with the scale of the forces which produced it—the magnificent operations amidst which it was accumulated. This was a period of great and frequent trappean eruption. Hence the conglomerate red offers a splendid specimen of rapid formation. This member of the devonian suite consists of large masses of gneiss, quartz, mica-slate, and hornblende rock, cemented in a paste of silicious sand, probably the debris of dissolved granite. The included portions bear all the marks of attrition, of violent tossing about in a troubled sea. Estimate the thickness of the whole deposit at its maximum of nearly ten thousand feet—consider what vast agencies were still at work, in tearing up and carrying off the spoils of the mountains—probably with but little pause or intermission in the violence of the action—and thus, not so much in the light of remote antecedents as of comparatively associated formations, will we be warranted in regarding these early courses in the work of creation. The fishes of the period all speak of its spasmodic character, mailed, plated, and completely inclosed in strong horny integuments; their heads, some of them, of entire uncovered bone, and their caudal fins propelling with the whole force of the vertebral column,—conditions of structure which give indications of the stormy seas whose waves they had to buffet, and of the conserving properties by which their forms and outlines have been transmitted to us so wonderfully entire.