Maryland Geological Survey 153 



Vprtical Total 

 thickness vpitioal 

 feet thickness 



Clay seam with a thin crystalline layer of limestone at middle 1.6 69.2 



Massive gray limestone, weathering to thin beds at top of cut. 



About 6 feet above base occurs Meristella prwnuntia 8.7 67.6 



Massive, somewhat crystalline limestone, dark gray in color. 

 Shale parting near middle. Near top of the unit occurs Rensse- 



Iccria mutaMlis 5.3 58.9 



Massive bed of gray, argillaceous, somewhat crystalline lime- 

 stone. Chert layer 2 feet above base. Lower part weathering 



nodular near top of cut 12.3 53.6 



Clay seam 1.5 41.3 



Massive, somewhat nodular, blue argillaceous limestone 4.8 39.8 



Clay seam 0.8 35.0 



Argillaceous, drab, somewhat nodular, massive bed of lime- 

 stone 1 3.5 34.2 



Thin-bedded argillaceous limestone with some cherty layers. . 4.7 30.7 



Heavy, blue, nodular limestone 1.0 26.0 



Shale parting 0.5 25.0 



Massive bed of gray limestone with numerous transverse 



calcite seams 3.6 24.5 



Thin-bedded, argillaceous, nodular limestone. Layers of dark 



chert throughout one heavy bed 15 feet above base of unit 16.3 20.9 



Massive gray limestone 2.6 4.6 



Massive gray limestone in a single bed filled with Gypidula 



coeymancnsls var. prognostica 2.0 2.0 



Concealed. 



Thickness of Keyser exposed^ 139.2 



X. Sections at Hyndman, Pennsylvania 

 Two good exposures of the Keyser member are seen in the vicinity of 

 Hyndman, a few miles north of the Maryland-Pennsylvania line, on the 

 western flank of the Wills Mountain anticline. These are designated Sec- 

 tion A and Section B. Section A is exposed in a quarry about 800 feet 

 west of the Baltimore and Ohio Eailroad station at Hyndman. It was 

 studied earlier by Schuchert and called by him the Lower quarry zone. 

 At the top of the section the Gypidula coeymwnensis var. prognostica zone 

 is exposed. About 30 feet below the Grypidula zone there is a 5-foot bed of 

 stroma toporoids. Few other fossils have been found in the Lower quarry 

 zone. The section begins at the Gypidula coeymanensis var. prognostica 

 zone in the extreme west end of the quarry. 



