624 Systematic Paleoxtology — Upper Devonian 



Pal^oneilo angusta Hall 

 Plate LXI, Fig. 13 



Palcconeilo angusta Hall, 1885, Pal. of N. Y., vol. v, pt. i, sec. ii, p. 344, pi. 

 xciii, fig. 11. 



Description. — Shell below medium size, elongate-elliptical, length more 

 than twice height. Postumbonal part of cai'dinal margin straight, declin- 

 ing from umbo; anterior extremity rounded; ventral margin curving 

 slightly, nearly straight in middle part; posterior extremity produced, 

 doubly emarginate. Valves low, convex with a slight sulcus in front of 

 umbonal slope. Umbo about one-third length from anterior end, low, 

 closely appressed, rising but little above hinge-line. Umbonal slope 

 slightly angular, postcardinal slope broad, divided longitudinally into two 

 parts by a low angular fold which extends to posterior extremity. Surface 

 bearing faint concentric striae save on postcardinal slope where the 

 striae become stronger, thread-like and are about 1 mm. apart. 



Length 17 mm.; height 7 mm. 



A single valve has been observed. It differs from the typical form in 

 being more elongate, surface smoother, lamellcse lines on postcardinal 

 slope more distant. It agrees, however, in its general features with the 

 species to which it is referred. The surface ornamentation distinguishes 

 this species from all other species of Paljeoneilo in the fauna. 



Occurrence. — Jennings Formation, Chemung Mebiber. Oakland- 

 Eedhouse Eoad. 



Collection. — Maryland Geological Survey. 



Pal^oneilo petila Clarke 

 Plate LX, Fig. 24 



Palwoneilo petila Clarke, 1904, Mem. N. Y. State Mus., No. vi, p. 311, pi. xv, 

 figs. 1-8. 



Description. — " This little shell in some features is similar to P. con- 

 siricta, having a sinuous posterior extremity and the arrangement of the 

 ligament pits as in that species. It is, however, always small, transversely 

 ovate, never so broad as in P. constricia; beak behind the anterior third of 

 the length, anterior margin subelliptic, basal margin convex, broadly 



