GEOLOGY. 



595 



species are not more tnan a yard long. It must have spread 

 terror on all sides. 



With the cretaceous seas were extinguished all those 



281. Fossil Shells of the Secondary Period. 



1, Turrilites cqtenata, Protogaa. 2, Oyster — Ostrrra columha (Lamarck), i, Terebratula. 

 4, ]\IammiUary Ammonite. 5, Striated ]>rautilu8 — Nautilus striatus. 



6, Curved Gvyphxn— GrypJuea incurva. 



races of strange reptiles, to whose voracity the exuberant 

 l^rood of ocean fell an easy prey. But at the same time 

 their mission Avas now inti'usted to voracious sharks of 

 enormous size, which for the first time appeared in the 

 waters of the globe. 



