140 The Lower Devonian Deposits of Maeyland 



tonoloway foemation 

 Fissile, platy, argillaceous, blue limestone. 



IV. Section % Mile Southwest of Rawlings 

 The Potomac River flows through a narrow gorge f mile south of 

 Eawlings Station where an uninterrupted section of the New Scotland 

 and Coeymans limestone and upper part of the Keyser is afforded in the 

 cuts of the Baltimore and Ohio Eailroad. 



The section ' begins south of the watchman's house. 



Helderbeeg Foemation 



Vertical Total 

 New Scotland Member thickness vertical 



feet thickness 



Concealed. New Scotland shale. 



Gray limestone, upper beds containing much chert. Spirifer 

 macropleurus fauna 30.0 158.7 



Coeymans Member 

 Massive, blue crystalline limestone, very fossiliferous, con- 

 taining Gypidula coej/manensis, Atrypa reticularis, crinoid 

 stems. Contains some irregular fragments at base. Thickness 

 approximate. The New Scotland and Coeymans limestone to- 

 gether are 39 thick 9.0 128.7 



Keyser Member 



Massive dark granular limestone. Brown sandy lines 2 feet 



above base of unit, containing stromatoporoids in upper 2 feet. 



Leperditia sp. abundant 7.4 121.7 



Shale 0.8 114.3 



Massive dark granular limestone 4.1 113.5 



Shaly limestone 2.8 109.4 



Massive dark granular limestone, upper 18 inches somewhat 



shaly 3.7 106.6 



Medium-bedded limestone, upper 9 inches shaly, containing 



stromatoporoids. Ostracods abundant 9 inches below top 2.4 102.9 



Shaly limestone 5.7 100.5 



Shaly limestone, upper 2 feet more massive. Band of chert 



at bottom and 3.8 feet above bottom of unit 13.4 94.8 



Very cherty limestone 1.8 81.4 



Shale 0.9 79.6 



Limestone 0.9 78.7 



Shale 0.5 77.8 



Measured by C. K. Swartz. 



