io Field Columbian Museum Geology, Vol. II. 



POLYCOTYLUS. 

 Cope, Proc. Amer. Phil. Soc. xi, 117, 1869. 



*latii'innis Cope, 1. c; Ext. Batrachia, etc. 36, pi. 1, ff. 1-12; An. 

 Rep. U. S. Geol. Surv. 1871, 388; ibid. 1872,320,335; Bull. 

 U. S. Geol. Surv. Terr. 27, 1874; Cretac. Vertebrata, 45, 72, 

 255, 1, vii, ff. 7, 7a; Leidy, Ext. Vert. Fauna. 279. — Niobrara 

 Cretaceous of Kansas. 



*ischiadicus Williston, postea, Niobrara Cretaceous, Kansas. 



This genus was based upon a portion of a propodial bone and 

 imperfect cervical and dorsal vertebrae. The ribs of the neck are 

 single-headed. 



PIRATOSAURUS. 

 Leidy, Cretaceous Rept. N. Amer. p. 29, 1865 

 PL1CATUS Leidy, 1. c. pi. xix, fig. 8. — Cretaceous, Minnesota. 



Based upon a single tooth. Believed by the author to be Cro- 

 codilian. The horizon is probably Niobrara, judging from the 

 accompanying fossils. If so, it would seem very probable that the 

 tooth belongs to a plesiosaur, though rather sharply conical in shape. 



NOTHOSAUROPS. 

 Leidy, Proc. Acad. Nat. Sci. Phil. 1870, 74. 



occiduus Leidy, 1. c. ; Rep. Geol. Surv. Terr. 1873, i, 345, pi. xv, ff. 

 11-23; Cope, Bull. U.S. Geol. Surv. Terr, i, 28, i8j^.(P/cs/o- 

 saitrus); Cretac. Vert. 1875, 256 {id.). — Laramie [?] Cretaceous, 

 Dakota. 



TAPHROSAURUS. 

 Cope, Proc. Amer. Phil. Soc. xi, 274, 1870. 



lockwoobi Cope, Ext. Batrachia, etc. 1869, 40 {P/i-siosa/tri/s); Proc. 

 Amer. Phil. Soc. xi, 274. — Cretaceous No. 1, New Jersey. 



OLIGOSIMUS. 

 Leidy, Proc. Acad. Nat. Sci. Phil. 1872, 39 (1873). 



GRANDjEVUS Leidy, 1. c. 40; Extinct Vert. Fauna, 286, 345, pi. xvi. 

 ff. 18, 19.— 



This genus and species were proposed for a detached caudal 

 vertebra of small size, without definite horizon, from Green River, 



