HUDSON RIVER BEDS NEAR ALBANY 537 



The occurrence of Pachydictya acuta, Rhyncho- 

 trema increbescens and Proetus parviusculus 

 would, hence, indicate a lower or middle Trenton age for these 

 bed's, which eoTrelation can, on account of the abundance andi 

 association of Diplograptus amplexicaulis, with 

 these fossils, be limited with a fair degree of 'exactness to the 

 mididile Trenton age. 



A remarkable and easily misleading feature of some beds in 

 this as well as in the Fitzgerald quarry is their great similarity 

 to some Lorraine beds at Waterford; for in all three localities 

 there occur gray, sandy argillaceous rocks with iron-stained fos- 

 sils, which it would be difficult to separate by their lithologio 

 aspect, but the foissil contents and a strong admixture of calcare- 

 ous matter in the rocks of the Brothers's quarry show that this 

 similarity is only accidental. 



Station 25. Ruscher's quarry, south Troy 



Directly south of the Brothers's quarry and in the strike of its 

 rocks lies another large quarry, Euscher's (station 25). The same 

 black shales, heavy sandstone banks and arenaceous limestone 

 beds', as well a® greenish shales toward the eastern part, are here 

 exposed. Diplograptus amplexicaulis is also quite 

 common. 



Station 26. Corner of Adams and 10th streets, Troy 



In the railroad cut at the corner of Adams and 10th streets in 

 North Troy, (station 26) in a compact, black argillaceous shale 

 Diplograptus amplexicaulis. Hall, and C o r y - 

 noides curtus, Nicholson, were found. These fossils and 

 the appearance of the rock leave no doubt of the identity of these 

 beds with those exposed in their direct strike in the Brothers'a 

 and Euscher's quarries in south Troy. No other exposures of 

 these beds have been met with farther north, in the investigated 

 area, though they undoubtedly continue in the direction indicated 

 hj the outcrops in Troy. 



