BRACHIOPODA. 247 



Genus Metaplasia Hall and Clarke 



cf. Metaplasia pyxidata Hall 



Plate 65, figure 14 



1859. Spirifer pyxidata Hall, Nat. Hist. N. Y. Pal., vol. 3, p. 428, pi. 100, figs. 9-12, 



1861. 

 1913. Metaplasia pyxidata Schuchert, Geol. Surv., Md. Low. Dev., p. 422, pi. 72, 

 figs. 11-12. 



Description — Shell small, length less than the width, the hinge line equal to the 

 greatest width of the shell; sub-elliptical in outline. The dimensions of a pedicle valve 

 are: Length 6 mm., width approximately 7 mm. 



Pedicle valve highly convex, elevated along the middle line into a pronounced median 

 fold with narrow sinus along the summit. Beak prominent, blunt and incurved. Sur- 

 face essentially smooth. 



Remarks — The pedicle valve of a small brachiopod resembles this species some- 

 what closely, but since there is nothing present in the collection to represent the brachial 

 valve, and since the specimen is incomplete no certain identification can be made. 

 This specimen studied differs from the figured specimens from New York and Maryland. 

 (1) in being considerably smaller, (2) in having a more prominent beak, (3) in having 

 steeply sloping postero-lateral margins, and (4) in having a total absence of surface 

 striations. 



Horizon — Upper beds. 



Figured specimen Nc. 27498, Walker Museum. 



Family Suessidae 



Genus Cyrtina Davidson 



Cyrtina ro strata Hall 



Plate 65, figure 13 



1857. Cyrtia rostrata Hall, Tenth Ann. Rept. N. Y. State Cab. Nat. Hist., p. 64. 

 1859. Cyrtia rostrata Hall, Nat. Hist. N. Y. Pal., vol. 3, p. 429, pi. 96, figs. 1-6; pi. 



98, figs. 8a-8b, 1861 

 1908 Cyrtina rostrata Clarke, Mem. N. Y. State Mus., vol. 9, pt. 1, p. 183, pi. 31, 



figs. 25-28. 

 1913. Cyrtina rostrata Schuchert, Geol. Surv., Md. Low. Dev., p. 423, pi. 71, figs. 

 10-16. 



Description — The only example at hand is an incomplete brachial valve which un- 

 doubtedly belongs to this species. Shell small, semi-circular in outline. The dimensions 

 are: Length 10 mm., width approximately 17 mm., the hinge line being equal to the 

 greatest width of the shell. Shell almost flat, or depressed convex, with a conspicuously 

 marked, slightly flattened mesial fold, which increases in width from the beak to the 

 anterior margin. Beak small and incurved a little over the hinge line. The surface 

 on each side of the fold is marked with 6 or 8 radiating plications, which are crossed by 

 finer, concentric, sharply zigzag lines. 



Remarks— Sufficient portion of the brachial valve is present to demonstrate the 

 outstanding features of this species — the semi-circular outline of the shell, the long, 

 straight hinge line, and the coarse, radiating plications. 



Horizon — Lower beds. 



Figured specimen No. 27495, Walker Museum. 



