. The story of the earth and man [microform]. Geology; Paleontology; Man; Géologie; Paléontologie; Homme. 220 THE STORY OP THE EARTH AND above a dozen largo species from the Upper Meso- zoic of England, and dates the first appearance of the turtles in England about the time of the l*ortland stone, or in the upper half of the Meso- zoic; but footprints supposed to be those of turtles are found- as far back as the Trias. Perhaps no typo of modern reptiles is more curiously special- ized than these animals, yet we thus find them contemporaneous with many generalized types, and entering into
. The story of the earth and man [microform]. Geology; Paleontology; Man; Géologie; Paléontologie; Homme. 220 THE STORY OP THE EARTH AND above a dozen largo species from the Upper Meso- zoic of England, and dates the first appearance of the turtles in England about the time of the l*ortland stone, or in the upper half of the Meso- zoic; but footprints supposed to be those of turtles are found- as far back as the Trias. Perhaps no typo of modern reptiles is more curiously special- ized than these animals, yet we thus find them contemporaneous with many generalized types, and entering into existence perhaps as soon as they. The turtles did not culminate in the Mesozoic, but go on to be represented by more numerous and larger species in the Tertiary and Modern. In the case of the crocodiles, while they attained perhaps a maximum toward the end of the Mesozoic, it was in a peculiar form. The crocodiles of this old time had vertebrae with a hollow at each end like the fishes, or with a projection in the front. At the end of the Mesozoic this was changed, and they assumed a better-knit back, with joints having a ball behind and a socket in front. In the Cretaceous age, species having these two kinds of backbone were contemporaneous. Perhaps this im- provement in the crocodilian back had something to do with the persistence of this type after so many others of the sea-lizards of the Mesozoic had passed away. Of the fishes of the Mesozoic we need only say that they were very abundant, and consisted of sharks and ganoids of various types, until near. Please note that these images are extracted from scanned page images that may have been digitally enhanced for readability - coloration and appearance of these illustrations may not perfectly resemble the original Dawson, J. W. (John William), Sir, 1820-1899. Toronto : Copp Clark
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