MARYLAND GEOLOGICAL SURVEY 149 



Section of Chambersburg Limestone One-Half Mile Northwest of Dickey, Pa. 



Martinsburg shale. Feet 



Fissile shale, limy at base 



Thick bed of dark-gray coarse crystalline crinoidal limestone, 



fossiliferous (Sinuites bed) 6 



Chambersburg limestone. 

 Nidulites bed. 



Thin-bedded cobbly, dark, fine-grained limestone containing 

 Diplotrypa appalachia, Plectambonites cf. P. sericeus, 



Leptaena sp., Pianodema cf . P. subaequata 37 



Rather massive gray to dove-colored fine-grained mottled lime- 

 stone banded in part 18 



Fine-grained platy to cobbly gray limestone with few Diplo- 

 trypa 30 



Tetradium cellulosum bed. 



Massive fine-grained dark limestone containing Beatricea and 



Tetradium cellulosum 34 



Caryocystites bed. 



Dark compact subgranular to crystalline limestone, with 



Caryocystites plates 8 



Concealed, 170 feet, of which probably at least 130 feet 



belongs to the Chambersburg 130 



Stones River limestone. 



Thin bedded pure fine even-grained drab limestone 



257 



The railroad cut just south of Fort Loudon exposes the Tetradium 

 cellulosum bed to advantage and here good fossils from this zone can be 

 had. Faulting has somewhat confused this section, but the locality is 

 of particular interest in showing an unconformable contact between the 

 Caryocystites and the overlying Tetradium cellulosum beds. The lowest 

 six inches of the latter consist of compact clayey limestone rilling irregu- 

 larities in the surface of the underlying bed. Evidence of a time interval 

 is also shown by the parasitic bryozoans and the expanded bases of 

 Cleioc'nnus which are attached to the eroded surface of the underlying 

 bed. 



