Maryland Geological Survey 47 



STEATIGEAPHIC AND PALEONTOLOGIC 

 CHAEACTERTSTICS 



The Eomney Formation ^ 

 introductory 



In sections wherever shown in Allegany and Washington counties, the 

 Eomney formalion is immediately underlain by the Oriskany sandstone 

 and the transition from sandstone to shale is abrupt. This contact may 

 be studied to advantage at Monster Eock, opposite Keyser ; on the Williams 

 Eoad SVo niiles southeast of Cumberland and at the iron bridge over Lick- 

 ing Creek, 1 mile east of Warren Point, Pennsylvania, just north of Wasli- 

 ington County, as well as at many other points. As will be shown in the 

 description of the sections the Eomney formation is composed of three 

 parts : the lower shales representing the Onondaga limestone and Mar- 

 cellus shales of Xew York and the succeeding shales and sandstone, the 

 Hamilton stage. It will be remembered that in the standard New York 

 section between the Oriskany sandstone and Marcellus shale is the 

 Ulsterian series of Clarke and Schuchert composed of the Esopus grit, 

 the Schoharie grit and Onondaga or Comiferous limestone.^ It was 

 long believed that there was no representative of these stages in Maryland 

 and that during that time there must have been a land area in western 

 Maryland. The evidence relied upon to support this view was the sup- 

 posed absence of the Onondaga fauna. The Onondaga fauna has, however, 

 recently been shown to be present in the lower member of the Eomney. 

 There is also a basal conglomerate at some localities in the Eomney con- 

 taining pebbles derived from the Oriskany sandstone which, in connection 

 with a conglomerate at the top of the Oriskany, indicates a temporary 

 emergence and later subsidence of the land. This structure is well shown 

 at the locality east of Warren Point where it was first noticed and described 

 by Eowe. Unconformity by erosion was described by Darton between the 



' The discussion of the Onondaga member is by Edward M. Kindle. The 

 remainder of the chapter is by Charles S. Prosser. 



- In the last edition of Handbook 19, New York State Museum, by Hartnagel, 

 the Esopus grit is transferred from the Ulsterian to the Oriskanian series (see 

 table i and p. 62). 



