MARYLAND GEOLOGICAL SURVEY 319 



" The surface of the operculum is concentrically striated. The shell 

 itself in some of the specimens is covered with fine longitudinal striae, 

 from five to ten in the width of a line. The shell varies in thickness in 

 different individuals. In some it is thin and composed of a single layer, 

 but in others it is much thickened by concentric laminae, and thus 

 approaches the structure of a Salterella. There are also fine engirdling 

 striae, and sometimes obscure subimbricating rings of growth." Billings, 

 1872. 



The above description with the emendation as to the ventral and dorsal 

 sides given by Walcott, will serve for the recognition of the poor frag- 

 ments found in the Maryland strata. 



Occurrence. ANTIETAM SANDSTONE. Eakles Mills, Maryland, and 

 the same horizon in Pennsylvania. 



Collections. Maryland Geological Survey, U. S. National Museum. 



Suborder CONULARIIDA 



Family TORELLELLIDAE Holm 



Genus SALTERELLA Billings 



SALTERELLA sp. 



Description. Certain layers in the lower part of the Tomstown lime- 

 stone have exhibited molds of small, hollow, slender shells with a striated 

 surface. These show that the shell is composed of several hollow cones 

 placed one within the other as in the genus Salterella. These remains are 

 too imperfect for description or illustration, but they are interesting on 

 account of their occurrence in the Tomstown limestone where fossils are 

 exceedingly scarce. 



Occurrence. TOMSTOWN LIMESTONE. Several localities east and 

 southeast of Waynesboro, Pennsylvania. 



Collection. II. S. National Museum. 



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