HUDSON RIVER BEDS NEAR ALBANY 501 



c e a , S t r o p h m e n a a 1 1 e r n a t a , E s c h a r o p o r a 

 recta. Ptilod'ictya acuta, caudal shield of a small tri- 

 lobite probably A s a p h u s y e t u s t u s , E n d o c e r a s (prob- 

 ably proteiforme), Ortlioceras, not well defined, 

 spiral univalves, O li a e t e t e s named C li . t e n u i s s i m a , 

 encrinal columns, Keceptaculites. 



In another paper (24) the same investigator states that the 

 Chaetetes with fine columns has been identified, in part at 

 least, as Stromatopora compacta, Billings, and ndds as 

 new from Rochdale a number of Ojathophylloid corals, among 

 them, with little doubt, Petraia corniculum, a caudal 

 shield of a trilobite which has been identified bv Ford as 

 Illaenus crassicauda, and a head of E c h i n o - e n c r i - 

 nites anatiformis. 



He also found in the continuation of the limestone belt across 

 the Hudson, 2f miles north of Newburgh ferry: O r t h i s lynx, 

 O. pectinella, Ehynchonella capax, Leptaena 

 sericea, Strophomena alternata, a new D i s c i n a 

 (later described as D. conic a), Chaetetes compacta, 

 very abundant. Oh. 1 y c o p e r d o n var. r a m o s u s , S c h i - 

 zocrinus nodosus, Echino-encrinites anati- 

 formis, probably O. tricenaria, and Petraia corni- 

 culum. 



The author adds: "These developments establish this beyond 

 doubt as a stratum of the Trenton limestone ''. A farther 

 conclusion which could be drawn, is that these faunas contain 

 no forms characteristic of or restricted to the upper Trenton, 

 while they distinctly point to a lower and perhaps in some de- 

 gree middle Trenton age for the beds; for Orthis tricen- 

 aria and Petraia c o r n i c u 1 u m are restricted to the lower 

 Trenton, Illaenus crassicauda occurs in the upper Low- 

 ville and Trenton limestone, Schizocrinus nodosus is 

 most abundant in the lower .Trenton, Ptilodictya acuta 

 and Escharopora recta occur only in the lower and cen- 

 tral part of the Trenton, Echino-encrinites anati- 

 formis is a middle Trenton form, and the abundant Chae- 

 tetescompactais restricted to the Black river. 



