MARYLAND GEOLOGICAL SURVEY 123 



Traces of this fauna have been found in Maryland, but neither these 

 nor the specimens from West Virginia are thought well-enough preserved 

 to warrant illustration and description. 



This lower division is about 600 feet thick and consists of massive and 

 thin-bedded pure dove limestone interbedded, especially toward the base, 

 with magnesian layers. Certain parts of the underlying Beekmantown 

 limestone are much like these in lithic character, but the presence of 

 bivalved pelecypod shells in the Stones River and their complete absence 

 in the Beekmantown serves to distinguish the two formations. No well- 

 exposed section of the Lower Stones Eiver was found in Maryland, but at 

 Martinsburg, West Virginia, the following section is more or less clearly 

 exposed in quarries and nearby natural outcrops. 



Section of Basal Beds of Stones River Limestone at Martinsburg, 

 West Virginia 



Feet 



Strata of Middle Stones River 



Light to dark drab limestone banded with thin earthy or magnesian 



seams 275 



Strata like the above but less well exposed 200 



Dark-gray to dove-colored, fine, even-grained pure limestone (quarried) . 100 

 Similar fine-grained, dove-colored limestone, increasing downward in 



magnesium (quarried) 100 



Section extends to the cherty top of the Beekmantown. 



675 



Railroad cuts along the Cumberland Valley Railroad north of Kauff- 

 man, Pennsylvania, eight miles north of the Maryland line, show the gen- 

 eral character of the division. This same band of outcrop continues south- 

 ward into Maryland and a number of localities show small outcrops of the 

 basal rocks. At Bostetter the very base of the formation is exposed at a 

 low angle of dip, with the result that a considerable area here is covered 

 with the cauliflower chert described under the discussion of the Beekman- 

 town limestone. This cauliflower chert marks the base of the formation 

 in the northern half of Maryland east of the Martinsburg shale belt, 

 and it is present in all the bands of outcrop west of this belt. In the 

 southern part of the area east of the shale belt, the Stones River rocks 

 are poorly exposed and their basal beds are marked by edgewise con- 

 glomerates quite similar to those of underlying formations. These con- 



