Maryland Geological Survey 331 



SCHUCHERTELLA DEEORillS (Hall) 



Plate LXr, Figs. 1,2 



Orthis deformis Hall, 1857, Tenth Rept. N. Y. State Cab. Nat. Hist., p. 44. 

 Orthis deformis Hall, 1859, Pal. N. Y., vol. iil, p. 174, pi. xa, flg. 13; pi. xv, 



fig. 3, 1861. 

 Orthothetes deformis Schuchert, 1897, Bull. U. S. Geol. Survey, No. 87, pp. 



296-297. 



Description. — " Shell suborbicular, lenticular. Ventral valve more 

 convex than the opposite, most elevated between the center and beak : beak 

 straight, or often distorted in consequence of having been the point by 

 which the shell was attached. Dorsal valve depressed convex, most ele- 

 vated near the beak: beak not extending beyond the hinge-line. Hinge- 

 line straight, equalling about three-fourths the width of the shell. Area 

 broad, flat, sometimes nearly on a plane with the axis of the shell. Fora- 

 men closed above, and filled below by the strong cardinal process. Surface 

 marked by prominent rounded striae, which increase by implantation, and 

 are crossed at intervals by distinct subimbricating concentric lines of 

 growth. The strige are distinctly tubular, with openings at the more 

 conspicuous lines of growth. The fine concentric striae are often scarcely 

 visible in the silicified sjicciinens." Hall, 1859. 



Length about 4 cm. ; width about the same. 



Occurrence. — Helderberg Formation, Keyser Member. Devil's 

 Backbone, Cash Valley. 



Collections. — Maryland Geological Survey, U. S. iSTational Museum. 



[Maynard.] 



ScHUCHERTELLA siNUATA (Hall aud Clarke) 

 Plate LXI, Figs. 3, -4 



Orthotlietes deformis var. sinuatus Hall and Clarke, 1892, Nat. Hist. N. Y., 

 Pal., vol. viii, pt. i, pi. 20, figs. 8 and 9. 



Description. — Two views of a specimen are figured but not described 

 by Hall and Clarke, which show the distortion of the beak and the median 

 sinus on the brachial valve. Hall says " Further examination will prob- 



