BRACHIOPODA. 83 



Hall's description — "Shell small, semielliptical, having a brilliant nacreous lustre; 

 hingeline crenulated, equalling or a little less than the greatest width of the shell below, 

 and sometimes terminating in more or less distinct angles. Dorsal valve concave. Ven- 

 tral valve sometimes regularly convex, flattened at the margins, often depressed-convex 

 in .the umbonal region and abruptly arched towards the front; beak very small and de- 

 pressed; area very narrow, linear, without foramen. The area of the dorsal valve is 

 often nearly as wide as that of the ventral valve. 



Surface apparently smooth, but under a lens showing very faint concentric lines 

 of growth, with sometimes obscure traces of radiating lines. 



The muscular impressions in the ventral valve extend more than half the length 

 of the shell. The divaricator muscular imprints are deeply depressed, elongate-ovates 

 narrowing above and somewhat widely separated below; while the occlusor impressions 

 are narrow-ovate spots on the thickened portion of the shell, and below these extends a 

 narrow elevated band separating the other impressions. In the dorsal valve, the anterior 

 and posterior occlusor muscular impressions are small and not strongly defined. The 

 cardinal process is slender, bifurcating, with a narrow rounded ridge extending from 

 its base down the middle of the valve. The interior of the shell, excepting the muscular 

 impressions, is studded with prominent scattered granules or papillae. The crenulations 

 on the hingeline are rather distant, but conspicuous." 



Occurrence — Specimens of this species are rare in the Mineola limestone of Mont- 

 gomery County. 



Genus Strophonella Hall 



Strophonella crassa Rowley 

 Plate 11, figures 12, 13 and 14. 



1894. Strophonella crassa Rowley, Am. Geologist, XIII, p. 153, figs. 4-6. 

 1897. Strophonella crassa Schuchert, U. S. G. S. Bull. 87, p. 438. 

 1909. Strophonella crassa Greger, Am. Jour. Sci., XXVII, p. 377. 



Rowley's description — "Shell semicircular, slightly eared at the cardinal extremities. 

 Heavy and thick for a species of this genus. Dorsal valve slightly concave from the 

 obsolete beak to the middle, convex beyond. Striae numerous, rather small and indis- 

 tinct on both valves, probably due in part to the state of "preservation of the type. Ven- 

 tral valve low-convex behind the beak, flat toward the circumference. Beak not in- 

 curved, slightly elevated, giving a wide, low, triangular cardinal area. Both valves have 

 areas but there is no deltidium. 



This species is apparently nearly related to 5. reversa Hall, but is much larger 

 form, with less concavity to the dorsal valve and less convexity to the ventral valve." 



Remarks — The writer has examined only one specimen of this species, one of Mr. 

 Rowley's paratypes. The pedicle opening is about twice as high in the pedicle valve 

 as in the brachial and is completely closed by stony matter in both. 



Occurrence — Snyder Creek shale, localtity 1, Callaway County. 



Genus Schuchertella Girty 



Schuchertella arctostriata (Hall) 

 Plate 15, figures 8, 9, 12; plate 24, figures 18-23. 



1843. Strophomena arctostriata Hall, Geol. N. Y., Rept. Fourth Dist., p. 266, fig. 3. 

 1897. Orthothetes chemungensis arctistriatus Schuchert, Bull. U. S. Geol. Surv., 87, 



pi. 296. 

 1909. Schuchertella arctostriata Grabau and Shimer, North American Index Fossils, I, 



pp. 229-230, figs. 280 a and b. 

 1911. Schuchertella chemungensis arctistriata Cleland, Bull. 21, Wisconsin Geol. Surv., 



p. 91, pi. 16, fig. 15. 



