Maryland Geological Survey 521 



obvious affinities of the species to the following H. ? iriplicala tends to 

 emphasize the relations to Kirkbya then suggested. The generic reference 

 is, therefore, at the present time, made doubtful. 



Occurrence. — Helderberg Formation, Keyser Member. Cumber- 

 land. 



Collection. — U. S. National Museum. 



Halliella ? triplicata n. sp. 

 Plate XCV, Figs. 17, 18 



Description. — This species has a surface ornament and sulcus almost 

 exactly as in H. ? seminulum and the variety longa just described, but 

 differs in the following respects: The ratio between length and height 

 is much less in H. ? triplicata, as a comparison of the respective measure- 

 ments will show. The most obvious difference, however, lies in the occur- 

 rence of three plications along the ventral edge of the present species. 



Length of valve .76 mm. ; height .57 mm. 



Occurrence. — Heldekberg Formation, Keyser Member. Cumber- 

 land. 



Collectio7i. — U. S. National Museum. 



Genus ^CHMINA Jones and Holl 



^EcHMiNA cuspiDATA Jones and Holl 



Plate XCV, Figs. 19-21 



JEchmina cuspidata Jones and Holl, 1869, Ann. and Mag. Nat. Hist. (4), vol. 



iii, p. 218, text fig. 2, pi. xiv, fig. 8. 

 JEchmina cuspidata Jones, 1870, Monthly Microscopical Journal, vol. iv, p. 



185, pi. Ixi, fig. 6. 

 JEchmina cuspidata Jones, 1S87, Ann. and Mag. Nat. Hist. (5), vol. xix, p. 



411, pi. xiii, figs. 2-4, 9. 



Description. — The discovery in x\merica of this well-marked species of 

 the Wenlock shales is not without considerable interest. The species has 

 been known to the writers for some time as a characteristic fossil of the 

 New Scotland beds of New York, and the extension of its range to West 

 Virginia is in keeping with their determination. 



