462 



GEOLOGY. 



1 k 



Fig. 208. — The Onondagan (Corniferous) Fauna. Vertebrata: a, Macropetalichlhys 

 sullivanii Newb. The figure represents the head of one of the most characteristic 

 Onondaga fishes. Coral: b, Zaphrentis ponderosa Hall. The figure represents a 

 medium-sized, simple, horn-coral. Brachiopoda: c, Stropheodonta concava Hall, and 



d, Spirifer acuminaius (Con.), two of the most characteristic Onondaga brachiopods; 



e, f, Cyrtina hamiltonensis Hall, two views of a species having a wide geographic 

 distribution, and a long geologic range in the Middle and Upper Devonian faunas; 

 g, Productella spinulicosta Hall, one of the earliest representatives of a genus which 

 became wonderfully abundant in the Upper Devonian, and gave rise to the typical 

 Producius of the Mississippian and Carboniferous faunas. Gastropoda: h, Platycerus 



[Continued on botto of p. 46'#.J 



