GEOLOGICAL SURVEY OF THE TERRITORIES. 333 



fessor Mudge's collection. The distal ones cannot readily be distin- 

 guished from those of L. proriger. 



LiODON PRORIGER, Cope, (Proc. Acad. Nat. Sci., 1869, 123, Trans. 

 Amer. Philos. Soc, 1870, 202.) — This is the most abundant of the 

 large species of the Kansas chalk. The writer found a muzzle c m- 

 sisting of premaxillary and portions of maxillary and dentary bones 

 in a spur of the lower bluffs of Butte Creek, and numerous frag- 

 ments of cranium and vertebrse on a denuded tract in the same 

 neighborhood. Both of these belonged to individuals of smaller size 

 than the type, the opi)ortunity of examining which I owe to Profes- 

 sor Agassiz. The more complete Butte Creek specimen belongs to 

 a huge animal ; the size is grandly displayed by a complete premax- 

 illary bone, with its projecting snout, and large fragments of the maxil- 

 lary. These furnish characters confirmatory of those already given as 

 above. The vertebrse are remarkable examples of flattening under 

 pressure, without fracture, some of them having a verticpJ diameter no 

 greater than one's hand. The cervicals are less flattened, and give the 

 impression that they were not transversely elliptic. This is consistent 

 with our knowledge of the perfect specimen, where it is, as described, 

 furnished with vertically ovate articular surfaces. In this the cup is 

 symmetrical and not distorted, but the ball is a little compressed by 

 pressure. 



The most important addition to the knowledge of this species, fur- 

 nished by the Butte Creek specimen, is the character of the quadrate 

 bone. A portion of the palatine bone, supporting these teeth, displays 

 the characters of the type, viz, the inner face vertical and deeper than 

 the outer, and forming a strong parapet of bone on the superior or 

 toothless aspect ; the outer face a little expanded laterally ; the bases 

 of the teeth exposed. It is proper to add that the locality ascribed to 

 the type specimen, " near Fort Hays, Kansas," which was given me, on 

 inquiry, is probably erroneous. Fort Wallace being the x^oint intended. 



LiODON DYSPELOR, Copc, (Proc. Amer. Philos. Soc, 1870, 574; 

 1871, 168, 172.) — This large reptile was first described from specimens 

 sent to the Smithsonian Institution from Kew Mexico. Professor 

 Mudge subsequently obtained it in Kansas, and on my late expedition 

 I had the good fortune to procure a large portion of another, on a sloi)ing 

 bluff on Butte Creek, fourteen miles south of Fort Wallace. This speci- 

 men is one of the most instructive which has yet been discovered, in- 

 cluding, as it does, fift}^ vertebrae from all parts of the column, a large 

 part of the cranium, with teeth, and both quadrate bones ; the scapular 

 arch complete, except back of coracoid on one side ; both humeri, radius, 

 and numerous phalanges of fore limb ; the pelvic arch complete, with 

 one hind limb complete to tarsus, with phalanges. The premaxillary 

 is wanting, but the adjacent suture of the maxillary remains. 



Measurements. — Estimated length of cranium, 5 feet, 1.570 metres ; 

 estimated total length, 75 feet. 



This specimen does not appear to be quite as large as the type, which 

 came from Fort McEae, New Mexico. The diameters of the vertebral 

 centra appear to be larger, in proportion to the length of the cranium, 

 than in the Mosasauriis dehayi^ hence, probably, the body had a greater 

 diameter. In estimating its length, rei'erence is had to the relations in 

 size of the caudal vertebra3 of the type of L. pr or iger^i and to the caudal 

 series of a small Liodon found on the bluffs of Butte Creek. The caudal 

 vertebra) are quite similar to those of tlie former j in the latter a series 

 of thirty centra exhibit very little diminution in size. On such a basis 

 the length would be about seventy-five feet. 



