294 GENERAL GEOLOGY. 



from the Inoceramus beds, and the only other materials of 

 any present or prospective value they possess, besides 

 lime, are the marls, which in future times will probably be 

 found useful upon some of the soils of the adjacent region. 



Fossils. The only vertebrate remains yet found in any of 

 the Cretaceous rocks of Iowa, are those of fishes. Those 

 found in the Inoceramus beds of Iowa are two species of 

 Squaloid selachians, one Cestratront, {PtycTiodus), and 

 three undetermined genera of Teliosts. Inoceramus proble- 

 maticus is usually quite abundant. Ostrea congesta not 

 unfrequent, but other molluscan remains are rare. Minute 

 Forammifera (probably Globalina) are sometimes met with 

 in great numbers. 



