G22 Systematic Paleoxtology — Upper Devonian 



Pal.i:oneilo maxima (Courad)' 

 Plate LX, Fig. 25 

 A few specimens liave been observed Avhieh. are not well enough pre- 

 served to permit confident identification. They are probably of this 

 species. 



Occurrence.^ — Jennings Formation, Parkhead Member. Two miles 

 nortli (if mouth of Town Creek, 1282, 1312. 

 Collection. — Maryland Geological Survey. 



Pal^oneilo brevis Hall 

 Plate LXI, Figs. 4-6 



Palwoneilo brevis Hall, 1870, Prelim. Notice Lammellibr., pt. ii, p. 10. 

 Palwoneilo brevis Hall, 1885, Pal. of N. Y., vol. v, pt. 1. sec. ii, p. 342, pi. 1, 



figs. 24-33. 

 Palwoneilo brevis Grabau and Shimer, 1909, N. Amer. Index Foss., vol. i, 



p. 400, fig. 510. 

 Palwoneilo brevis Cleland, 1911, Bull, xxi, Geol. Survey Wis., p. 101, pi. xx, 



figs. 6-7. 



Description. — "Shell small, ovate, or ovate-subtriangular ; length 

 about one-third greater than the height ; basal margin gently curving, with 

 a slight constriction toward the posterior extremity. Cardinal line 

 arcuate. Anterior end usually short and regularly rounded. Valves 

 convex below, gibbous in the middle and on the umbonal ridge. Beaks 

 usually at about the anterior third or a little posterior thereto, prominent, 

 moderately elevated above the hinge-line. Umbonal slope marked by a 

 slight flattening of the shell, which produced a gentle constriction in the 

 postinferior margin. This depression is rarely margined on each side 

 by an undefined elevation. Surface marked by fine, even, concentric 

 striae; the casts exhibiting only the stronger elevations which give an ir- 

 regiilar appearance to the concentric striae. Anterior muscular impression 

 very strongly marked. Posterior scar large and shallow. Hinge marked 

 by numerous minute crenulations. Three specimens of this species meas- 

 ure respectively 21, 20, and 14 mm. in length, and 14, 12, and 10 mm. 

 in height. This species is allied to P. constricta, but is more gibbous, 



' For synonymy and description see page 238. 



