Maryland Gkological Survey 18? 



Hill about 4 miles north of Oldtown; B. & 0. R. E. cut at Hancock Sta- 

 tion, W. Va. ; on road about half way between Eomney and Hanging Keek, 

 W. Va. ; on the Eomney-Hanging Eock Eoad about ^ mile north of 

 Eomney, W. Va. 



Collections. — Maryland Geological Survey; Xew York State Museum; 

 American Museum of Natural History. 



Genus SPIRIFER Sowerby 



Spirifer mucronatus (Conrad) 



Plate XVII, Figs. 10-18 



Probably Terebratula pennata Atwater, 1820, Amer. Jour. Sci. Arts, vol. 11, 



p. 244, pi. i, figs. 2, 3. 

 Delthyris mucronata Conrad, 1841, Fifth Ann. Rep. Geol. Surv. N. Y., p. 54. 

 Spirifer mucronata Billings, 1856, Canadian Nat. Geol., vol. i, p. 474, pi. vii, 



figs. 9, 10. 

 Spirifer mucronata Rogers, 1858, Geol. Penna., vol. ii, pt. ii, p. 828, fig. 668. 

 Spirifera mucronata Billings, 1861, Canadian Jour., n. ser., vol. vi, p. 254, 



figs. 59-62. 

 Spirifera mucronata Hall, 1867, Pal. N. Y., vol. iv, p. 216, pi. xxxiv, figs. 1-32. 

 Spirifera pennata Keyes, 1891. Johns Hopkins Univ. Circ, vol. xi, p. 29. 

 Spirifer mucronatus Hall and Clarke, 1893, Pal. N. Y., vol. viii, pt. ii, pp. 14, 



17, 36, pi. xxix, fig. 8, pi. xxxiv, figs. 13-22. 

 Spirifer pennatus Schuchert. Bull. U. S. Geol. Surv., No. 87, p. 401. 

 Svirifer mucronatus Clarke, 1903, N. Y. State Mus., Bull. 65, p. 321. 

 Spirifer mucronatus Grabau and Shinier, 1909, N. Am. Index Fossils, vol. i, 



p. 330, fig. 421. 

 Spirifer mucronatus Cleland, 1911, Fossils and Stratigraphy Med. Devonic 



Wisconsin, p. 80. 



Description. — Shell medium size; more or less gibbous; cardinal areas 

 low, and cardinal angles sometimes truncate but usually extended and 

 often prolonged into mucronate points Avhich give the hinge-line a length 

 of two to five times that of the shell. Ventral valve often scarcely more 

 convex than the dorsal ; beak small and incuiTed over the narrow cardinal 

 area which is longitudinally striated : mesial sinus is sharply defined quite 

 to the apex and limited by angular plications which are stronger than 

 the adjacent ones. The sinus is generally shallow and rounded in the 

 bottom, but sometimes flat or with a small fold in the center. In the 

 interior is a small striated muscular area. Dorsal valve moderately con- 



