242 Systematic Paleontology — Middle Devonian 



A considerable number of specimens of this species were obtained from 

 the Hamilton shales of Maryland. Hall identified the species from the 

 Hamilton group, near Cumberland, Md. (Pal. jST. Y., vol. v, pt. i, Lamel- 

 libranchiata ii, p. 339) and the Maryland specimens agree fully with the 

 figures of the New York specimens. This is a sharply differentiated 

 species and is distinguished by its deeply emarginate posterior margin; 

 strong, elevated, distant, lamelliform concentric striae, with finer striae 

 between; strong umbonal ridge, with depression above it and broad con- 

 spicuously marked sinus below. 



Length, 16-20 mm.; height, 7-11 mm. 



Occurrence. — Eomney Formation, Hamilton Member. East bank 

 Evitts Creek below Wolfe Mill ; Williams Eoad f mile east of Queen City 

 Hotel, Cumberland; Williams Eoad \ mile east of Queen City Hotel, 

 Cumberland; B. & 0. E. E. cut at 21st Bridge; McCoys Ferry; south- 

 west of McCoys Ferry. 



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

 American Museum of Natural History. 



Palaeoneilo tenuistriata Hall ( ?) 

 Plate XXVII, Fig. 7 



Palaeoneilo tenuistriata Hall, 1870, Prelim. Notice Lamellibranchiata 2, p. 9. 

 Palaeoneilo tenuistriata Hall, 1885, Pal. N. Y., vol. v, pt. i, Lamellibranchiata 



ii, p. 336, pi. xlix, figs. 1-12, 14, pi. xciii, fig. 13. 

 Palaeoneilo tenuistriata Keyes, 1891, Johns Hopkins Univ. Circ, vol. xi, p. 29. 

 Palaeoneilo tenuistriata Clarke, 1903, N. Y. State Mus., Bull. 65, p. 479. 

 Palaeoneilo tenuistriata Grabau and Shimer, 1909, N. Am. Index Fossils, vol. 



i, p. 399, fig. 510c. 



Description. — Shell large, ovate-elliptical; length more than one- third 

 greater than the height; basal margin regularly curving; posterior end 

 doubly truncate ; cardinal line gently arcuate ; anterior end short, rounded. 

 Valves convex, gibbous above the middle and in the umbonal region; 

 beaks at about the anterior third, moderately prominent, nearly straight, 

 little elevated above the hinge-line; the posterior end of the shell is de- 

 pressed-convex, with a more or less distinct depression extending to the 

 post-inferior extremity from just posterior to the beaks, giving a trunea- 



