46 NEW YORK STATE MUSEUM 



black shales. It is, however, obvious that the sandstones have 

 become more silicious and are prevailingly gritty, often coarse and 

 assuming the character of an arkose, as notably at Duanesburg. 

 The top layer of the sandstones frequently contains' numerous mud 

 pebbles inclosed in the sandstone. 



The following fossils were collected along Schoharie creek : 



Sphenophycus latifolius (Hall^) (r) 



Climacograptus typicalis Hall (c) 



Taeniaster schohariae nov. (rr) 



Conularia trentonensis Hall var. multicosta nov. (rr) 



Eurypterida : Dolichopterus f rankf ortensis ; Pterygotus sp. 



While in the Schoharie valley the Schenectady beds can not be 

 follow^ed to their contact with the overlying Brayman shales, this i 

 can be done along a small northern branch of the Cobleskill between 

 Central Bridge and Howes Cave, which has been pointed out by 

 Grabau (title 56, page 102) as an excellent exposure of the 

 Brayman shales. Here about 120 feet of Schenectady shales 

 and sandstones are exposed in the ravine above and below 

 the road. The lower portion consists prevailingly of dark gray to 

 brownish green, sandy shales with black argillaceous shales in thin- 

 ner seams. These change upward into purely sandy shales, which 

 grade into a sandstone about 20 feet thick that is followed by 

 the Brayman shale. The lower shales furnished great quantities 

 of Sphenophycus latifolius and many fragments 

 of eurypterids, among these chelicerae of Pterygotus, and cara- 

 paces of Pterygotus prolific us, Eurypterus 

 pristinus, Dolichopterus cf. frankforten- 

 s i s and Hughmilleria cf. magna. These eurypterid 

 remains could be traced into the bottom of the topmost sandstone 

 bed. Thus we see that here the eurypterid fauna indicative of the 

 Schenectady formation reaches close to the Brayman shales which ! 

 are supposed to be of Upper Siluric age (see postea page 54). 



Another series of outcrops of the middle and lower Schenectady I 

 formation is found along the Schoharie creek from Central Bridge 



1 This is die type locality of the species. Hall states of the occurrence of 

 the latter : " This species occurs in considerable abundance near Schoharie, 

 in the bed of the creek, in the central part of the Hudson River group. I 

 have not seen it in any other locality." We have not been able to find 

 Gebhard's old locality at Schoharie, but as is seen from the lists, have 

 observed this remarkable seaweed in sometimes immense quantities in other 

 outcrops, as at Kellum's quarry near Schenectady and in the Rotterdam 

 Junction section. 



