390 New York State Museum 



marine Mount Marion beds the Cardiff shales ; or that 

 the former are the time equivalent of the Moscow and 

 Ludlowville and the latter, of the Cardiff and Skaneateles. 

 The Hamilton beds, including the Marcellus, have an 

 aggregate thickness of about 1500 to 1600 feet in New 

 York state. 



The Marcellus beds (Hall '39) were named from ex- 

 posures at Marcellus, Onondaga county and now include 

 the black shales and the Cherry Valley limestone (Clarke 

 '03 ). 1 The Marcellus black shales follow the Onondaga 

 quite abruptly and an unconformity is indicated in east- 

 ern New York (Chad wick '27). There are about 200 

 feet more or less of these shales. Typically the Mar- 

 cellus is a black bituminous, pyritiferous, very fissile 

 shale, which is also characterized by numerous concre- 

 tions of carbonate of lime scattered through certain por- 

 tions of it. These concretions vary in size from a few 

 inches to several feet in diameter and appear to be most 

 abundant near the middle of the bed. The Marcellus 

 occurs in the Hudson valley and extends across the State, 

 thinning westward. Near the base of the black shale 

 are included calcareous layers characterized by goniatites 

 (cephalopods), the Cherry Valley (Agoniatite) lime- 

 stone (Clarke '03) which extends from the Schoharie 

 area to Ontario county as distinct layers. The fauna of 

 the Marcellus black shales is meager and in the east 

 distinctly Hamilton in character. The characteristic 

 brachiopod Liorhynchus limitaris is generally found, also 

 the pelecypod Limulicardium marcellense. The pteropod 

 Styliolina fissurella occurs in thin bands in countless 

 numbers. Other species are the brachiopods Chonetes 

 wucronatus, Leiorhynchns mysia, Strophalosia truncata, 



1 Cardiff shale of type locality, which lies below the Mottville 

 and disappears westward before Cayuga lake, belongs with Mar- 

 cellus formation (see page 391). 



