FOSSIL FOOT-STEPS. 



rocercal, the tail being unequally lobed as in fig. 1, which is the 

 tail of the shark, and the vertebral column running along the 

 upper lobe. On the other hand, in nearly all the living species, 



the tail is homocercal as in fig. 2, which is the tail of a herring, 

 the vertebral column not extending to the upper lobe. 



We have remarked that the first tracks of reptiles are met with 

 in this system of deposits. Below we represent the appearance 

 of these footprints as observed in England and Germany. It 



will be perceived that there are two impressions which always 

 accompany each other, and they are not unlike the human hand, 

 hence the animal was named ckeirotherium or hand beast. This 

 animal was for a long time supposed to be allied to the kangaroo, 

 and like it a marsupial, i. e. having a pouch in which to carry its 

 young; but more recently Prof. Owen, from a careful examina- 

 tion of teeth and other bones found in the new red sandstone, has 

 determined it to belong to the class of batrachians, or frogs, toads, 

 salamanders, &c., and from the peculiar structure of its teeth, 

 ho has given to this genus the name labyrinlhodon, or labyrinth 

 tooth. Besides the tracks just described, are found those of tur- 

 tles, of a little lizard with a bird-like beak, and the trails of 

 molluscs, and vermes, and the ripple marks of the ancient seas. 

 By far the most remarkable tracks occurring in the new red sand- 

 stone group, are those of gigantic birds, the foot-prints being sev- 

 enteen inches long, and the stride of the bird from four to six 

 feet. It is somewhat remarkable that nearly all the fossil foot 



