Maryland Geological Survey l'J3 



In Maryland this species occurs less frequently than either Spirifer 

 mucronatvs or S. granulosus and most of the specimens are internal 

 impressions. For this reason it is not always easy to separate S. auda- 

 culus from S. granulosus ; however, the size, shape and narrower plications 

 of the fonner generally distinguish the species. Hall's description of the 

 species states that the surface is "marked by from twenty to thirty 

 simple plications on each side of the mesial fold and sinus " while the 

 Maryland specimens rarely show twenty clearly marked plications. An 

 examination, however, of the New York type specimens indicates that 

 part of them scarcely show more than eighteen sharply defined plications. 

 In general S. audaculus is readilj^ distinguished from 8. mucronatus by 

 its larger size, much greater convexity, high ventral cardinal area, and 

 absence of extended hinge-line; from S. granulosus by its smaller size, 

 narrower plications, and absence of granulose surface. 



Length, 25-35 mm.; width, 35-45 mm. 



Occurrence. — Romney roEMATiON, Hamilton Member. Williams 

 Eoad, S^z-o miles southeast of Cumberland ( ?) ; Williams Road, 14 mile east 

 of Queen City Hotel, Cumberland; east bank Evitts Creek below Wolfe 

 Mill; on Hancock-Harrisonville Eoad about 2 miles north of Hancock; 

 McCoys Ferry; on National Road, I/2 mile west of Licking Creek; east 

 side Warrior Mt. east of Rush; B. & 0. R. R. cut at Hancock Station, 

 W. Ta. (?). 



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

 American Museum of Natural History. 



Spirifer acuminatds (Conrad) 

 Plate XVIII, Fig. 10 



Delthyris acuminata Conrad, 1S39, Third Ann. Rep. N. Y. Geol. Surv., p. 65. 

 Spirifer acuminata Hall, 1857, Tenth Rep. N. Y. State Cab. Nat. Hist., p. 135. 

 Spirifera acuminata Hall, 18G7, Pal. N. Y., vol. iv, pp. 198, 234, pi. xxix, figs. 



9-18; pi. xxxv, fig. 24. 

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

 Spirifer acuminatus Hall and Clarke, 1893, vol. vii, pt. ii, pp. 31, 39, pi. xxxix, 



figs. 39-42. 

 Spirifer acuminatus Schuchert, 1897, Bull. U. S. Geol. Surv., No. 87, p. 380. 

 13 



