GEOLOGICAL SURVEY OF THE TERRITORIES. 413 



oblique to the axis of the vertebra. The dense layer of the bone is 

 thrown into numerous rugosities and ridges, as in C. propython. 



What is more characteristic is the robust and even swollen form of 

 the crowns of the teeth, and their slightly rugose enamel for the basal 

 three-fourths the height. There are no facets. In the Kansas speci- 

 men there are twelve teeth in the dentary bone. 



Eotten limestone upper cretaceous, of Pickens County, Alabama, 

 and yellow chalk of Kansas. 



CLIDASTES CINERIARTJM, (COPE.) 

 (Proc. Amer. Philos. Soc, Dec, 1870, p. 583.) 



The largest species of this genus, as indicated by the zygosphen artic- 

 ulation of the vertebrae. 



The locality where it was found furnished also the L. mudger, but the 

 specimens were taken from the gray bed, perhaps the same that produced 

 the JElasmosaurus platyurus, Cope. They consist of vertebrae and a ptery- 

 goid tooth. There are two anterior dorsals, three lumbars, and one 

 caudal. The articular faces of the dorsals are broad vertical ovals. 

 They increase in width on the lumbars till on the last of these they as- 

 sume the sub-pentagonal form characteristic of many species, and which 

 is still more marked on the caudal. The centrum of the anterior dor- 

 sal is much compressed; interiorly slightly concave longitudinally reg- 

 ularly and prominently convex transversely. Conversely, the rims of the 

 cup and ball are strongly expanded, the latter with surrounding groove. 

 The diapophyses of the lumbars are of considerable length, exceed- 

 ing in this respect those of Mosasaurus we possess, where these parts are 

 preserved. On the median of the lumbars the inferior surface of the 

 centrum first becomes truncate or plane, and separated from that below 

 the diapophyses, which become slightly concave. The expansion for the 

 ball becomes more abrupt and striking on these vertebrae. The caudal 

 is a little more compressed than the lumbars, and presents the charac- 

 ter of coossified chevron bones. These are slender and longitudinally 

 grooved. 



A single pterygoid tooth was found in the matrix on one of the dorsals. 

 The basis is short and much swollen ; the crown curved, acute, a little 

 compressed, and with an obuse cutting edge posteriorly. 



Measurements, 



Vertebrae, &c, from gray bed : 



M. 



Anterior dorsal, length of centrum 0. 0608 



Anterior dorsal, depth of articular ball 038 



Anterior dorsal, width of articular ball 038 



Anterior dorsal, diameter behind diapophyses 029 



Anterior dorsal, depth of articular face for rib 022 



Lumbar, length of centrum „ 06 



Lumbar, depth of ball 037 



Lumbar, width , 039 



Lumbar, length of remnant of diapophysis 046 



Lumbar No. 2, length of centrum 055 



Lumbar No. 2, width of zygosphen 0182 



Caudal, length of centrum , 041 



Caudal, depth of cup 04 



Caudal, width 04 



