of course, could not exist, in the circumstances, a single appearance to sanction the belief that the two human creatures whom he saw walking together among the trees at sunset had been “developed from infusorial points,” not created mature. The evidence would, on the contrary, lie all the other way. And in no degree does the geologic testimony respecting the earliest Ganoids differ from what, in the supposed case, would be the testimony of Eden regarding the earliest men. Up to a certain point in the geologic scale we find that the Ganoids _are not_; and when they at length make their appearance upon the stage, they enter large in their stature and high in their organization. FISHES OF THE SILURIAN ROCKS—UPPER AND LOWER. THEIR RECENT HISTORY, ORDER, AND SIZE. But the system of the Old Red Sandstone represents the _second_, not the _first_, great period of the world’s history. There was a preceding period at least equally extended, perhaps greatly more so, represented by the Upper and Lower Silurian formations. And what is the testimony of this morning period of organic existence, in which, so far as can yet be shown, vitality, in the planet which man inhabits, and of whose history or productions he knows anything, was first associated with matter? May not the development hypothesis find a standing in the system representative of this earliest age of creation, which it fails to find in the system of the Old Red Sandstone? It has been confidently asserted, not merely that it _may_, but that it _does_. Ever since the publication, in 1839, of Sir Roderick Murchison’s great work on the Silurian System, it had been known that the remains of fishes occur in a bed of the “Ludlow Rock,”—one of the most modern deposits of the _Upper_ Silurian division; and subsequent discoveries both in England and America, had shown that even the _base_ of this division has its ichthyic organisms. But for year after year, the lower half of the system,—a division more than three thousand feet in thickness,—had failed, though there were hands and eyes busy among its deposits, to yield any vertebrate remains. During the earlier half of the first great period of organic existence, though the polyparia, radiata, articulata, and mollusca, existed, as their remains testified, by myriads, fish had, it was held, not yet entered upon the scene; and the assertors of the development theory founded largely on the presumed fact of their absence. “It is still customary,” says the author of the “Vestiges of Creation,” in his volume of “Explanations,” “to speak of the earliest fauna as one of an elevated kind. When rigidly examined, it is not found to be so. IN THE FIRST PLACE, IT CONTAINS NO FISH. There were seas supporting crustacean and molluscan life, but _utterly devoid of a class of tenants who seem able to live in every example of that element which supports meaner creatures_. This single fact, that only