184 



GEOLOGY. 



tana, North Dakota, New Jersey, and England, they probably fre- 

 quented the continental waters somewhat widely, and belong more 

 to the sea life; than to the land life from which they sprang. 



The second type, Ichthyornis (Fig. 416), consisted of small birds, 

 scarcely larger than pigeons, and tern-like in aspect, endowed with great 

 powers of flight, and armed with teeth set in sockets. In contrast with 





s**>. 



Fig. 416. — Ichthyornis victor, a Cretaceous toothed bird of flight, ^ natural size. 



(Restored by Marsh.) 



Hesperornis, the anterior parts, especially the wings and keel, were 

 strongly developed, while the legs and feet were small and slender. 

 Their biconcave vertebra and other skeletal features, as well as their 

 small brains, show primitive reptilian relations. Their habitat was 

 the same as that of Hesperornis, and yet the two were farther apart 

 structurally, than any two types of birds now living (Marsh). 



Several genera of birds, embracing altogether about 30 species, 



