REPORT OF THE STATE PALEONTOLOGIST I903 1 57 



The construction of this assemblage as a whole as indicative of 

 a very late upper Siluric marine fauna is justified and we would 

 therefore put together the entire mass of the strata 550 to 600 feet 

 thick, as appertaining to this horizon, that is the series of limestones 

 and shales extending from the reefs bordering the north flank of 

 Mt Joli, southward almost to the first palpable shear zone. 



In the layers of the south flank of the mountain which strike 

 n. 30° w., are essentially vertical but with many undulations and 

 irregular inclinations toward the north, and are thin, fairly pure 

 limestone strata from 2 to 5 inches in thickness separated by 

 sandy shale masses, fossils have been found : 



Hindia (apparently identical with Ortonia sp. 



foregoing) Ampyx hastatus Ruedemann 



Subretepora Tretaspis reticulatns Ruedemann 



Dalmanella testudinaria Dalman (very common) 



Rafinesquina sp. Calymmene callicephala Green 



Strophomena sp. strongly geniculate Pterygometopus cf. intermedins Wal- 



form (very common) cott 



Parastrophia hemiplicata Hall small Ptychopyge ulrichi Clarke (common) 



form Illaenus americanus Billings 

 Zygospira cf. uphami Winchell & 



Schuchert 



This very striking though small array of species is emphatically 

 indicative of early Siluric age, w^e might say in a general sense 

 equivalent to the Trenton, but can not escape the inference that it 

 is early Trenton with suggestions of Pretrenton age. The trilobites 

 are specially noteworthy, for Ampyx hastatus and Tre- 

 taspis reticulatus have been found before only in the lower 

 Trenton conglomerate of Rysedorph hill near Albany and definitely 

 indicate not the Trenton fauna normal to the Mississippian province 

 of that time, but the invading fauna from the Atlantic province 

 whose closer affiliations are with European species. 



Two spots in the sea w^all have afiforded these fossils, one not far 

 from the south end of the cliff where were taken 



Calymmene callicephala Parastrophia hemiplicata 



Dalmanella testudinaria Zygospira 



Rafinesquina 



These were from calcareous nodules embedded in the shales. 



