LIKK 



paucity of crinoids and corals, and a notable absence of fishes. 



ig. ,}(>; shows some of the characteristic forms. 



Oriskany fauna. The Oriskany fauna was a sand-loving fauna 

 \\hiih followed the Helderberg into the interior apparently by a 

 similar route. Its place of origin is not known with certainty, but 

 its habitat was probably on the Atlantic coast. It was bound by 



any ties to the Helderberg fauna, but contained distinctive 



atures, implying a partly separate origin. On the whole, this 

 fauna was essentially an assemblage of well-fed mollusks and mol- 

 lusroids, with but a sprinkling of other types. Brachiopods were, 

 on the whole, the most distinctive forms. 



f 



Fig. 364. ORISKANY FOSSILS. Brachiopods: a, Rcnsselaria etwees (Eaton); a 

 representative of a genus restricted to the Helderbergian and Oriskany (see Fig. 

 363, d); l>, Ilippiirionyx proximus Van., one of the most characteristic fossils of the 

 arenaceous Oriskany beds; e, Camarolcechia barrandci (Hall), one of the Lrge 

 rhynchonelloid shells of the Oriskany; d, Spirifcr mnrchisoni Castel, and c, S. arcno- 

 SH* (Con.), two of the most characteristic Oriskany species, the first occurring 

 throughout the fauna, the second mainly in the fauna of the arenaceous beds; 

 /, Slrophcodonla magnified Hall, a species which sometimes grew to be four or five 

 inches across. The genus has its great expansion in the Devonian. The figures 

 are much smaller than the fossils, the largest shells being 4 to 5 inches across. The 

 large si/.e of the Oriskany brachiopods may be appreciated by comparison with Fig. 

 363, the brachiopods of which are reduced to the same extent as those of this Fig. 



Onondaga fauna. The Onondaga fauna was distinguished 

 from the preceding by hosts of marine fishes of divergent types. 

 From this time on fishes were abundant in the epicontinental waters 

 of America and Europe, and doubtless ranged widely over the seas. 



