SEA-SERPENTS. 141 



denizens of land?" These creatures lived in the Cretaceous 

 period. The remains found in this region were mostly those of 

 reptiles and fishes. Thirty-five species of reptiles are known 

 from Kansas alone, representing six orders, and varying in 

 length from ten to eighty feet. One was terrestrial, four were 

 fliers, the rest inhabited the ocean. "When they swam over 

 what are now the plains, the coast-line extended from Arkansas 

 to near Fort Riley, on the Kansas River, and, passing a little east- 

 ward, traversed Minnesota to the British possessions, near the head 

 of Lake Superior. The extent of sea to the westward was vast, 

 and geology has not yet laid down its boundary ; it was probably 

 a shore now submerged beneath the waters of the North Pacific." 



Other very elongated marine reptiles of this period, but with 

 much thicker bodies, are called, by Professor Cope, Elasmosaurs. 

 In this group, which is not yet fully worked out, occur such 

 genera as Cimoliosaurus, Polycotylus, Polyptychodon,. and others. 

 But it seems a pity that they should be in any way separated 

 from the Plesiosaurs, which they strongly resemble (see chap, iv., 

 Plate III.). Though not sea-serpents, we have introduced them 

 here because they flourished at the same time, and lived in the 

 same seas with the Mosasaurs and other forms of that group. The 

 very large teeth, with strongly marked ridges, of the Polyptychodon 

 are abundant in the Cambridge Greensand that underlies the 

 chalk, and represent a very huge animal 



In our illustration, Plate XIIL, the artist has represented 

 the Elasmosaurus * (of Cope) with its long thin neck stretched 

 out in search of food on the bed of the sea. Professor Cope 

 thus describing this monster, in language which seems some- 

 what fanciful says, " Far out on the expanse of this ancient 

 sea might have been seen a huge snake-like form, which rose 

 above the surface, and stood erect, with tapering throat and 

 arrow-shaped head, or swayed about, describing a circle of 



1 Greek elastnos, plate; sautos, lizard : probably on account of the shape 

 of the paddles. 



