GEOLOGY AND PALEONTOLOGY OF THE SCHOHARIE VALLEY 



191 



Trilobites are well represented in the Schoharie grit. C a 1 y m - 

 m e n e p 1 a t y s [fig. 117], the last and the largest of the genus, 

 differs so little from its predecessor in the Niagaran that differ- 



Fig. 117 Calymmene platys 



ence in size is almost the only notable character. The hypostomae 

 of the two species are, however, quite distinct. Another charac- 

 teristic type is Phacops cristata [fig. 118], distinguished 

 from other species of the genus by the axial row of spines which 



Fig. 118 Phacops cristata 



extend as far as the pygidium, the short stout spines on the genal 

 angles, the strongly protuberant glabella, and the dichotomous 

 division in the annulations of the pygidium. Dalmanites 

 anchiops var. ar m a t u s [fig. 119] is largely represented by 

 pygidia, the form of which, together with the upcurving basal 

 spine, is characteristic. The head or cephalon when well pre- 



