Apr. 1903. NortTH AMERICAN PLESIOSAURS—WILLISTON. 9 
dorsal vertebre from the Cretaceous, probably Benton, of Clark 
County, Arkansas. Cope suppressed the generic name as of a genus 
not sufficiently differentiated from Cimoliasaurus. 1 believe, however, 
that both genus and species are valid; and that the former will include 
some of the species from Kansas. Lambe has identified the species 
from the Belly River Cretaceous of Canada, but it seems to me that 
the identity must be more or less problematical. 
ELASMOSAURUS. 
Cope, Proc. Acad. Nat. Sci; Phil. 1868, 68. 
*PLATYURUS Cope, I. c.; Notes on Geology, Leconte, 1868, 68; Proc. 
Bost. Soc. Nat. Hist. 1869, 266; Amer. Nat. iii, 87; Ext. 
Batrachia, etc. 1869, 47, ff. 7-12, pl. 1, ff. 1-9, pl. 11; Amer. 
ius Sol, 1570, 140, 200;Amer. Nat.'v, 47; Rep. U.S. Geol: 
Pw Lelie Togie1304,.1072, 320, 330; Cretac. Vert. 1875, 44, 
Meee? FOseisUliot). o-pcxeOl, ourv.. Letr:. 111, 1877,°578;: Amer. 
Nat. xxil, 7243 Pedy ae etas| Or. S0ly Xl1k{-1O70, 3923 Prod, 
Meade Nat.eoci, | hils1870; 9,185 kydekker, Cat. Foss. Rept. 
Brit. Museum, nu, 181 ( Crymol/asaurus).—Fort Pierre Cretace- 
ous, Kansas. 
INTERMEDIUS Cope, Proc. Amer. Phil. Soc. 1894, 112.—-Fort Pierre 
Cretaceous, South Dakota. 
ORIENTALIS Cope, Proc. Acad. Nat. Sci. Phil. 1868, 313; Proc. Bost. 
Soc. Nat. Hist 1869, 266; Geological Surv. New Jersey, 
Cook, Append. (1868), 1869, 7333 Amer. Nat. 1869, 87; Ext. 
Pereaciia, Fete 1500, 44.755, -pl. 11, f. 10> Amer. -[our., Scu. 
Pong e305 Gretac. Vert. 1375,1.255;bull.’U:.S. Geol. Surv. 
Perl 7 7)5075.570; Alm. Nat. xi, 1877, 3113 Leidy, Proc. 
Acad. Nat. Sci. Phil. 1870, 22 (Descosaurus).—Greensand No. 
4, New Jersey. 
SERPENTINUS Cope, Bull. U. S. Geol. Surv. Terr. 111, 578, 1877; Amer. 
Nat. xi, 1877, 311.—Niobrara Cretaceous, Nebraska. 
The genus “L/asmosaurus was founded upon a nearly complete 
series of vertebre obtained near the vicinity of Fort Wallace, Kansas, 
wrongly ascribed to the Niobrara epoch. The neck was very long. 
The incomplete girdles are also known. No additional material has 
been ascribed to the type species since the original description by 
‘Cope. 
