292 C. SCHUCHERT — LOWER HELDERBERG-ORISKANY FORMATIONS 



is older, in part at least; while the Cayuga, Ontario, zone is certainly the 



youngest. In the beds of the latter region occur most of the Middle 

 Devonic species, and here the Oriskany is directly overlain by the Onon- 

 daga limestone. In New York the Esopus intervenes between the Oris- 

 kany and Onondaga or Schoharie, and the time interval thus indicated 

 may be occupied in the Cayuga region by the Oriskany. 



The conspicuous Devonic character of this fauna is the presence of 

 Cysliphyllum, HeliopJiyllum, and PhiUipsastrea among the corals ; Slrophe- 

 odonta, llippariony.r, Pentamerella, Amphigenia, Splrifers with long hinges 

 and one with plicated fold and sinus, Amboculia, Pentagonia, and partic- 

 ularly Rensselasria, Meg ah inter is, and Centronella among the Brachiopoda ; 

 Actinopteria, Palseopinna, and My tllarca among the Pelecypoda ; an abun- 

 dance of large platyceroids among the Gastropoda ; and of the trilobites 

 Phncops, Dalmanites (Odontocheile), and Dalmanites (Chasmojis). 



Table of the Oriskanian Fauna 

 (Named species only. For local distribution, see pages 300-331.) 



Corals, 10 species. 



Zapltrentis incondita Billings. . . 

 cingulosa Billings. . . 



" rcemeri Hall 



CysLiphyllum sulcatum Billings. 

 Heliophyllum exiguum Billings. 

 Favosiles hemisphericus Troost. 



conicus Hall 



gotlandicus Lamarck. . 



turbinatus Billings. . . 

 PhiUipsastrea affinis Billings... 



Echinodermata, 7 species. 



Anornalocyslites disparilis Hall. 



Edriocrinus sacculus Hall 



Homocrinus proboscidalis Hall 



Technocrinus andrewsi Hall. . . 

 s<-ul])tns Hall 

 spinulosus Hall . . 

 " st, -tat us Hall 



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