A second fact which attests the primordial character and fixedness of species is, that every species as it first appears, is not in a transition state between one form and another, but in the perfection of its kind. Science has indeed discovered an ascending order in creation, which agrees marvellously with that given in the book of Genesis: first, vegetable productions; then the moving creatures in the sea; then terrestrial animals; and finally man. Naturalists, who utterly reject the Scriptures as a divine revelation, speak with the highest admiration of the Mosaic account of the creation, as compared with any other cosmogony of the ancient world. While there is in general an ascending series in these living forms, each was perfect in its kind. Agassiz says that fishes existed contemporaneously with species of all the invertebrate sub-kingdoms in the Taconic, or sub-Cambrian strata. This is the extreme limit of known geological strata in which life is found to have existed. As the evolution of one species out of another requires, according to Darwin, millions of years, it is out of the question to trace these animals beyond the strata in which their remains are now found. Yet "crabs or lobsters, worms, cuttle-fish, snails, jelly-fish, star-fish, oysters, the polyps lived contemporaneously with the first known vertebrate animals that ever came into being--all as clearly defined by unmistakable ordinal or special characters as they are at the present moment."[52] The foot of the horse is considered by zooelogists as "one of the most beautiful contrivances in nature." The remains of this animal found in what is called the Pliocene Period, show the foot to have been as perfect then as it is now.