Such a general view of the subject of organic remains seems to give plausibility to the hypothesis of organic development. But the tables are turned when we descend to particulars. The idea of a distinct stirps or germ for each great class of animals and plants seems to me to destroy an essential feature of the hypothesis. It supposes that law produces at once a vertebral animal and a flowering plant; for the first, certainly, we find in the very lowest of the fossiliferous rocks. "The lower silurian," says Sir Roderick Murchison, in 1847, "is no longer to be viewed as an invertebrate period, for the onchus (a genus of fish) has been found in the Llandeilo Flags, and in the lower silurian rocks of Bala." It is also a most important fact, that this fish of the oldest rock was not, as the development scheme would require, of a low organization, but quite high on the scale of fishes. The same is true of all the earliest species of this class. "All our most ancient fossil fishes," says Professor Sedgwick, "belong to a high organic type; and the very oldest species that are well determined fall naturally into an order of fishes which Owen and Mueller place, not at the bottom, but at the top of the whole class."--_Discourse on the Studies of the University_, &c. 5th edit. p. lxiv. pref. This point has been fully and ably discussed by Hugh Miller, Esq., in his late work, "The Footprints of the Creator, or the Asterolepis of Stromness." The asterolepis was one of these fishes found in the old red sandstone, sometimes over twenty feet long; yet, says Mr. Miller, "instead of being, as the development hypothesis would require, a fish low in its organization, it seems to have ranged on the level of the highest ichthyic-reptilian families ever called into existence."