76 University of Kansas Geological Survey 



for the seizure of mammals than the slippery fishes that the 

 Gavials seek. 



The earliest fossil Crocodiles are found in rocks of Triassic 

 age in both Europe and North America. These early types, 

 however, are of a much more generalized kind than are the 

 modern ones. These Triassic forms are more like the Gavial 

 in shape, but the vertebrae are not concavo-convex as in the 

 modern, but biconcave, and this peculiarity of the vertebrae 

 continues into the Cretaceous and nearly through it, when the 

 modern type of vertebrae takes their place. 



The order is divided into three different suborders, based upon 

 the structure of the head, especially the palatine bones and the 

 nasal openings and the structure of the vertebrae. The first, 

 Parasuchia, includes the earliest types, such as Belbdon, and 

 had amphicoelian vertebrae. The second, the Mesosuchia, have 

 also biconcave vertebrae, and included the Jurassic and most of 

 the Cretaceous forms. The third, the Eusuchia, with procoelian 

 vertebrae, is the modern type. 



But two crocodilians have been described from Kansas, both 

 Mesosuchian, with a long, gavial-like head. Both are known 

 only from very scanty materials, so that it is difficult to say 

 much about them. The older one was described — but not 

 named — by me from the Lower Cretaceous of Clark county as 

 follows : 33 



"A single vertebra, wanting the neural arch, but otherwise 

 well preserved, I refer somewhat doubtfully to Hyposaurus or 

 a closely allied form. It has the articular surfaces nearly flat, 

 with the rims sharp ; the body is gently concave on the sides 

 and below, from in front back, and with striae near each rim 

 for about half an inch. The surface elsewhere is smooth and 

 even, without venous foramina. A transverse section through 

 the middle would give the greater part of an elliptical figure, 

 with the lower side somewhat flattened. Only the base of the 

 pedicels is present, and there is no indication of a sutural union. 

 Springing from them, or possibly from the body itself produced 

 above to meet the arch, there is, on each side, a stout transverse 



33. Kansas Univ. Quart., in, p. 3, pi. I, ff. 4, 5. 



