236 SYSTEMATIC PALEONTOLOGY 



notched on the posterior side; the notch occupying nearly one-quarter 

 of the circumference of the valve on the outer margin and extending 

 nearly to the center of the valve, its border thickened, especially at the 

 base, which is rounded, with the center marked by a slightly projecting 

 point, marked by strong, irregular, concentric undulations parallel to the 

 margin, but interrupted by the border of the notch. Brachial or free 

 valve moderately convex, most prominent near the center, its surface 

 marked by fine, even, thread-like, radiating striae, which increase both by 

 bifurcation and intercalation, and become stronger toward the border 

 of the shell."- Weller, 1903. 



This interesting brachiopod ranges in age from the Trenton to the 

 Richmond, the best localities, however, being in the Trenton of New York 

 and the Maysville of the Ohio Valley. In the Cumberland Valley the 

 species is known only in the lower part (Corynoides bed) of the Martins- 

 burg shale. 



Occurrence. MARTINSBURG SHALE (Corynoides bed). Williamsport, 

 Maryland. 



Collections. Maryland Geological Survey, U. S. National Museum. 



Family CRANIIDAE 



Genus PHOLIDOPS Hall 



PHOLIDOPS CINCINNATIENSIS Hall 



Plate LIV, Figs. 23, 24 



Pholidops cincinnatiensis Hall, 1872, 24th Kept. New York State Cab. Nat. 



Hist, pi. vii, fig. 10. 

 Pholidops cincinnatiensis Meek, 1873, Pal. Ohio, vol. i, p. 130, pi. v, fig. 2. 



Description. " Shell small, ovate in outline. Larger valve about one- 

 fifth longer than wide, with height one-third to one-fourth the breadth. 

 Apex obtuse, near half way between the middle and the larger end. 

 Anterior end narrowly rounded, posterior end somewhat more broadly 

 rounded, or almost sub-truncate. Surface ornamented by six or seven 

 sub-imbricating marks of growth. Smaller valve unknown. 



"Length, 0.14 inch, 0.12 inch; height of larger valve, 0.04 inch/' 

 Meek, 1873. 



