92 NEW YORK STATE MUSEUM 



Mariacrinxis, a subgeneric expression of Melocrinus, attains its 

 culmination in this fauna. Coronocrinus, Cordylocrinus, Cam- 

 arocrinus, Brachiocrinus and Aspidocrinus are not known 

 elsewhere. 



Corals. The development of explanate Favositea is notable 

 and in direct accord with their progress toward culmination in the 

 Onondaga limestone. 



Striatopora and Aulopora attain their culmination in the 

 Devonic. 



Pleurodictyum here makes its first appearance. 



Zaphrentis has a meager representation ( Z. r o e m e r i ) ; its 

 culmination is in the Onondaga limestone. The same is true of 

 Cladopora and Vermipora. 



Of the stromatoporoids, Girty has described five species of 

 Syringostroma, a genus not known in earlier faunas but occurr- 

 ing in the middle Devonic. 



Sponges. Hindiafibrosa, though occurring in the Siluric, 

 is here at its most profuse development, and its existence is carried 

 upward into the Onondaga limestone (Onondaga county). 



Negative elements 



Trilobites. The Siluric genera Bumastus, Calymmene, 

 S t a u roc e p h a 1 us, Encrinurus, S p h ae r e x o ch u s, Platy- 

 notus, Crotalocephalus, are absent. 



Ceplialopods. The group is but very sparsely represented. There are 

 no representatives of the genera Ascoceras, Actinoceras, 

 Oncoceras, Hormoceras, Cyrtoceras (of Siluric type) 

 Pentacoceras, Hexacoceras, or any characteristic Siluric types. 



Lamellibranclis. Ambonychia, Anomalodonta, Telli- 

 nomya, Clidophorus and Modiolopsis are wanting. 



BracMopods. The entire family of the Trimerellidae 

 (Trimerella, Dinobolus, Monomerella, Rhinobolus, Lin- 

 gulops, Lingulasma), which was so profusely represented in the 

 late Siluric, is absent. 



Orthis (s. s. ) disappears in the Niagaran ; probably also, P 1 e c t - 



