46 NEW YORK STATE MUSEUM 



exposed at many other places in the State. Some Favosites were 

 found in the Rondout at the railroad cut. The lower part of 

 the formation is transitional into the beds below and in one of 

 the beds near the base of the Rondout there is an abundance of 

 Cladopora rectilineata Simpson, a fossil very charac- 

 teristic of the Cobleskill limestone of eastern New York and 

 New Jersey. 



Cobleskill and Decker Ferry limestones. The Cobleskill lime- 

 stone was formerly correlated as Niagaran, but it is now known 

 to be above the Salina. In this cut the Cobleskill and Decker 

 Ferry formations will be described together since for lack of 

 fossils it is not easy to state where the division between them 

 should be drawn. The total thickness of these two formations 

 is 35 feet. The upper 30 feet are characterized by the great 

 abundance of the small coral Cladopora rectilineata 

 Simpson which gives to the rock a mottled appearance. Fossils- 

 other than the corals were not found. This coral, it should be 

 observed, is also very abundant in the Cobleskill and Decker 

 Ferry at the Nearpass section in New Jersey. In color the roclc 

 is of various shades of brown. There are seams of shaly matter 

 between some of the more massive beds. The upper 10 feet 

 are finer grained and more subject to fracture and shattering. 

 The lower 20 feet are more silicious and compact and in position 

 correspond with the Rosendale cement bed as shown in Ulster 

 county. The lower 4 feet are characterized by the absence of 

 corals and by the presence of the following species : 



Atrypa reticularis Linne 

 Camarotoechia litchfieldensis Schuchert 

 Chonetes jerseyensis Weller 



Longwood shale (High Falls shale and Binnewater quart- 



zite). This term was introduced by Darton 1 to designate the 



red shales and light colored quartzites which in the region under 



consideration and in that extending farther southwestward into- 



New Jersey, occupy a position between the Helderberg (=Decker 



Ferry in part) limestones and the Shawangunk conglomerate- 



(=Green Pond). Darton states [p. 382]: "There are similar 



shales having- the same relations in Ulster county, N. Y., where 



they have been considered equivalent to the Clinton formation." 



In 1894 Darton 2 published a section in Ulster county where the 



red shales above the Shawangunk conglomerate were designated 



the Medina and the name Clinton was used for the quartzites 



above the red shales. As the names Medina and Clinton were 



iGeol. Soc. Am. Bui. 1893/5:382. 



2N. Y. State Mus. 47th An. Rep't. 1894. p. 530, fig. 8. 



