5fi2 Systematic Paleontology — Upper Devoxian 



The species is not common and has been found freely only at one 

 locality, on the National Eoad, jnst east of Millstone, where it occurs in 

 a yellow argillaceous sandy shale. It is also reported from the soft olive 

 sliales of the lower beds of the series at the foot and on the slope of 

 Polish Mountain, on the iSTational Road. 



Occurrence. — Jennings Formation, Parkhead Member. Xational 

 Eoad, east of Millstone ; Polish Mountain, east of Gilpin. 



Collection. — Maryland Geological Survey. 



Chonetes oaklandensis n. sp. 

 Plate L, Figs. 14-18 



Description. — Shell transverse, semielliptieal, hinge-line longer than 

 width of shell, cardinal angles acute. Ventral valve convex, regularly 

 rounded from umbo to anterior margin, greatest convexity near middle 

 of valve ; concave toward cardinal angles. Umbo narrow, elevated. Area 

 narrow, not distinctly shown in individuals observed. Dorsal valve con- 

 cave, the concavity less than convexity of pedicle valve. 



Surface bearing 50 to 60 fine, rounded, straight stris which increase 

 by intercalation and occasional bifurcation. Stria3 obsolete near cardinal 

 angles. About 4 stride occupy the space of 1 mm. near the anterior 

 margin of shell. The striae are crossed by very fine concentric strife which 

 are visible only in very perfectly preserved specimens. A few coarser 

 concentric growth lines occur near anterior margin. 



The cardinal margin bears 3-4 short spines on each side of umbo which 

 are directly obliquely outwards. Interior muscular markings not observed. 



Length 6 mm. ; width 9 mm. 



This species resembles C. scitulus in its outline. The stria?, however, 

 are cpiite different. In C. scitulus many of the intercalated strias are 

 very short, being present only near the margin. In this species the striae 

 are much finer while the intercalated striae are much longer. It closely 

 approaches C. lineata of the Hamilton of New York, but difi:ers in being 

 less convex, valves not distinctly flattened in the middle, spines more 

 numerous. It belongs, liowever, to the group of C. lineata and C. yandel- 

 lana. 



