HUDSON RIVER BEDS NEAR ALBANY 535 



Ctenobolbina subrotunda sp. n, 



Lepidocoleus jamesi, Hall & Whitfield sp. 

 In the more argillaceous rock were found: 



Diplograptus (Glyptograptus) amplexicaulis Hall 



D. foliaceus, Murchison 



Proetus cf. parviusculus, Hall 



The combination of Diplograptus amplexicaulis 

 with Bchizocrinus nodoisus and Proetus cf . par- 

 viusculus is fairly sufficient evidence of the Trenton age 

 of the shales and sandstones in Fitzgerald's quarry; for D. 

 amplexicaulis occurs typically in the lower and middle 

 Trenton and Schizocrinus nodosus and Proetus 

 parviusculus (see next station) are known from the Tren- 

 ton only. Ctenobolbina subrotunda is nearest re- 

 lated to the Trenton species (C t . f u 1 c r a t a and Gt. crassa, 

 Ulrich) of that genus {see description, p. 576). 



Station 24. Brothers's quarry, south Troy 

 The outcrop south of Troy where Whitfield 26 years ago col- 

 lected the Trenton graptolite, could not be precisely located; at 

 least no information of the former occurrence of limestone in that 

 neighborhood could be obtained. There were, however, several ' 

 localities found which furnished ample evidence of the presence 

 of Trenton fossils and which, as they contain calcareous sand- 

 stone banks with intercalated impure limestone banks and shales, 

 may be identical with Mr Whitfield's collecting ground. 



The most important locality is the Brothers's or Lavery^s quarry 

 station 24), at the brow of the hills east of south Troy. Diplo- 

 graptus amplexicaulis is found here in great numbers 

 in black, argillaceous shale at the east side of the quarry and 

 more sparingly in association with Corynoides calicu- 

 1 a r i s in similar beds at the opposite side of the quarry. 



In calcareous sandstone beds which contain dark impure lime- 

 stone banks consisting of brachiopod shells, in the middle part 

 of the quarry, occur brachiopods,, a number of which were first 

 collected by Gilbert Van Ingen of Columbia university and kindly 

 left with the writer; and one bed is filled with bryozoans. The 

 beds yielded: 



