HUDSON RIVER BEDS NEAR ALBANY 513 



Hu'dison,, hiave, besides the grarptolites, yieldied omly few other 

 fossils, and nione of decisive taxonomic value {see p. 569); that 

 these graptolites are. restricted to these beds ; that, farther, these 

 beds are hidden av^^ay in a huge mass of mostly barren shales and 

 sandstones, and that, finaily, this whole mass of rocks, which 

 contains Trenton, Utica and Lorraine beds in similar lithologic 

 development, is in New York as well as in Canada cut olf from 

 the neighboring terranes by extensive faults, thus apparently also 

 frustrating all attempts at a stratigraphic solution of the prob- 

 lem. 



DISCOVERY OF OUTCROPS (STATIONS) WITH FOSSILS 



It is only in view of these extreme difficulties which besiege the 

 Hudson river problem that the writer presents his observations 

 on this problem in an area which appears insignificant in com- 

 parison with the great geographic extension of the beds in ques- 

 tion. But only by restriction to a definite small territory has it 

 been possible to visit every outcrop and, what is still more im- 

 portant, to collect in every outcrop most exhaustively and min- 

 utely. As a gratifying result of this method, there Vv^ere found in 

 the region described in the introduction, 29 localities which fur- 

 nished fossils. These, with 7 localities known before, give 36 sta- 

 tions with fossils. These can be arranged according to their fos- 

 sil contents in four zones, which, following the general strike 

 of about ni 20° e of the rocks in this part of the Hudson river 

 valley, extend from n n e to s s w. The stations will be 

 described according to these zones {see map). 



DESCRIPTION OF STATIONS 



A LORRAINE BEDS 



Station 1. Cohoes falls of the Mohawk river 



All along the lower Mohawk and specially from the high falls 

 of the river at Oohoes to the islands in the Hudson river opposite 

 the mouth of the Mohawk, is exposed an enormous mass of 

 greatly contorted rocks (a sketch of these contortions is given by 

 Mather, 4, pi. 2, fig. 1) of mostly shaly character; that is argil- 



