406 Systematic Paleontology 



New York. The similarity to the Niagaran species was observed by Whit- 

 field. The strong plications and greater width separate it from S. eriensis. 



" Most of the specimens of S. eriensis were found at Williamsville. A 

 few, however, came from the cement quarries in north Buffalo. Width of 

 the pedicle valve illustrated, 10 mm.; length, 8.5 mm. Width of the 

 brachial valve illustrated, 7.5 mm. ; length, 6 mm." Qrabau, 1900. 



Only one specimen has been found in Maryland in the Cash Valley 

 section associated with Dalmanella clarhi. S. eriensis is very closely re- 

 lated to S. modestus and S. plicatus of Maryland. It may be distinguished 

 from the former by its larger size and plications, and from the latter which 

 it so closely resembles by its less incurved beak, greatest width near middle 

 of valve, acute cardinal angles of brachial valve. 



Occurrence. — Helderberg Formation', Keysee Member. Cash Valley. 



Collection. — Maryland Geological Survey. 



[Maynard.] 



Spirifer cyclopterus Hall 

 Plate LXIX, Pigs. 8-10 



Spirifer cycloptera Hall, 1857, Tenth Ann. Rept. N. Y. State Cab. Nat. Hist., 



p. 58, figs. 1-5 (wrongly labeled 8. perlamellosa) . 

 Spirifer cyclopterus Hall, 1859, Nat. Hist. N. Y., Pal., vol. iii, p. 199, pi. xxv, 



figs, la-lz (? figs. Ip, Iq). 

 ? Spirifer concinnus Hall, 1859, ibidem, pi. xxv, figs. 2a- 2/ (not figs. 2g-2i). 

 Spirifer cyclopterus Weller, 1903, Geol. Surv. N. J., Pal., vol. iii, p. 314, pi. 



xxxviii, figs. 1-6. 



Dcscripiion. — " Shell semicircular; extremities of the hinge-line more 

 or less symmetrically rounded : ventral valve gibbous ; beak moderately 

 elevated, more or less incurved; sinus moderately deep, curved on the 

 sides, and nearly fiat in the middle : dorsal valve very convex towards the 

 middle, the mesial fold abruptly elevated and very prominent; beak little 

 elevated above the hinge-line, and scarcely incurved; area moderate, 

 scarcely extending to the extremity of the hinge-line; foramen large. 

 Shell marked by five to seven rounded plications on each side of the 

 mesial line, concentrically marked by fine close imbricating lamellose 

 strife, which are more or less prominent, depending on the condition of 

 preservation in the shell : surface of lamella ornamented by short fine 



