714 



GEOLOGY 



seas of the Middle Oolitic stage. Crinoids also rose again to prom- 

 inence, though their diversity was not great. They departed from 

 Paleozoic forms in various ways. Most of them lived in shallow 

 water, as most of the Paleozoic types had; but there is evidence 



Fig. 484. JURAS>K ( <i;i,KNTERATA AND EcHINODKKM ATA . f/aild/*. Tlnltn- 



nastrcea prolifera Hecker, a complete corallum, and the latrra! surface of 

 a costal septum, enlarged; c, Thecosmilia Irirlmlnnm ((loldf.); '/, 

 crinus briareus Mill; e, Cidaris coronata Goldf. 



