6o NEW YORK STATE MUSEUM 



The following named fossils were enumerated as the most im- 

 portant : 



"Ophileta complanata (possibly Ophileta com- 

 pacta), O. levata, O. sordida (Maclurea sor- 

 dida), Orthoceras primigenium." Other univalves 

 were noted but not identified. A network of " fucoidal fronds " 

 might be Bythotrephis antiquata. The fossils of the 

 neighboring Trenton at the east were absent from this rock and it 

 was believed to lie beneath the Trenton, both strata having an east- 

 ward dip. It was called the Calciferous.^ 



In October 1880, Dwight^ found at the Rochdale locality another 

 remarkable assemblage : " great numbers of Orthocerata and other 

 fossils, many of which are not reported as occurring in New York 

 State." In lithology this rock was identical with that previously 

 assigned to the Calciferous. Orthocerata were abundant and dis- 

 coidal gastropods very plentiful. In addition to its own peculiar 

 fossils, it contained the " fucoids " and other types of the adjacent 

 Calciferous. Dwight hesitated to announce the exact stratigraphical 

 position of this new fossil assemblage. The wealth of cephalopods 

 separated it very sharply from any other known terrane in the 

 United States below the Black River-Trenton, to which it was in- 

 ferior. In its numerous orthoceratite cephalopods it resembled the 

 Quebec group of Canada. 



In 1882 Diwght'' reported tracing the Calciferous in this strip to 

 a point five miles below Poughkeepsie. In addition to the above- 

 named ''Calciferous" fossils he announced in this paper: A large 

 Holopea and smaller ones not identified, many Pleurotomaria re- 

 sembling Canadian forms, a minute Ophileta n. sp., a Mur- 

 chisonia resembling gracilis of the Trenton, one or two orthides, 

 many undeterminable fragments of Bathyurus, Chaetetes ly- 

 c o p e r d o n var. r a m o s a, not hitherto reported below the Tren- 

 ton, 25 to 30 species of Orthocerata, all apparently new in the 

 United States, two species of Lituites and a Cyrtoceras. In 1884* 

 a number of these fossils were described with figures; trilobite frag- 

 ments were provisionally assigned to the genus Bathyurus (B. 



1 The ledges at the summit of the hill north of Alson DeGarmo's house 

 on the Pleasant Valley road belong, in part at least, to Dwight's Calci- 

 ferous locality. 



2 Amer. Jour. Sci., Ser. 3, 21 :78. 



2 Proc. Amer. Assoc. Adv. Sci. (Montreal meeting), v. 31. Abstract Aug. 

 1882, p. 3-6. 



4 Amer. Jour. Sci., Ser. 3, April, 1884, 27:249-59. 



