Maryland Geological Survey 85 



Keyser Member. — Limestone, massive and very nodular in its lower 

 part, more shaly and thin-bedded above. Contains numerous reefs of 

 corals and stromatoporoids. Thickness 270-290 feet. Zone of Spirifer 

 modestus. 



Coeijmam Meinher. — Massive crinoidal limestone. A sandstone occurs 

 in the lower part of this division at Elbow Eidge. Thickness 9-13 feet. 

 Zone of Gypidula coeymanensis. 



New Scotland Member. — Consisting of two parts: (a) limestone, con- 

 taining much Mliite chert, the latter forming a large part of the whole ; 

 (b) a thick bed of shale forming the upper part of the member in the 

 Cumberland area. Thickness 12-45 feet. Zone of Spirifer macropleurus. 



Becraft Member. — Gray crystalline limestone containing much inter- 

 bedded black chert. Thickness 80-125 feet. Zone of Spirifer concinnus. 

 This member is present only in the eastern sections. 



The Keyser Member 



Character and Thickness. — The Iveyser member is named from 

 Keyser, West Virginia, Avhere the strata are admirably exposed in the 

 quarries of the Standard Lime and Stone Company on the Baltimore and 

 Ohio Eailroad about f mile east of the town. 



The Keyser forms the major part of the Helderberg of Maryland. The 

 lower beds are very nodular, while the upper beds are more shaly. Massive 

 ledges of corals and stromatoporoids are present at several horizons, being 

 especially prominent in the upper more shaly beds in the Cumberland 

 area. A few strata contain chert. West of Hancock the thickness varies 

 from 270 to 290 feet. Its precise thickness has not been ascertained east 

 of that place. 



Fauna. — The Keyser contains a rich coral and brachiopod fauna, the 

 composition of which will be considered more fully in the chapter on 

 correlation. 



Keyser-Toxoloway Boundary. — The lower limit of the Keyser mem- 

 ber is well defined by a marked change in the character of the sediments, 

 the rather massive and very nodular limestone of the lower beds of this 

 member contrasting strongly with the platy, fissile, thin-bedded limestone 



