Maryland Geological Survey 617 



appears to have been a rather rare form in the Naples fauna of that 

 region. In Maryland, however, it is much more generally diffused. 



The tyjiical form of the species from the Styliola limestone of New 

 York is here figured for comparison with the Maryland specimens. 



Occurrence.' — Jennings Formation, Genesee Member. Eomney 

 Eoad 3I/2 niiles southwest of Burlington, West Virginia; Wolfe Mill on 

 National Eoad, 3 miles northeast of Cumberland; hill on Williams Eoad 

 near Cumberland. Woodmont Meimber, Naples Fauna. Gilpintown 

 on National Eoad about 80 feet east of Town Creek. 



Collection. — Maryland Geological Survey. 



Genus I'ARACARDIUM Barrande 

 Under this term have been placed certain paleoconchs which, as has 

 been observed above, are similar to Buchiola in all particulars except the 

 general expression of the surface. The latter is many-ribbed and in its 

 typical expression as shown in P. doris, these ribs lack the chevroned 

 character of Bucliiola. Yet in some species there is an evident though 

 fine concentric ornament on ribs and furrows alike. The hinge structure 

 is identical with that of Bucliiola showing a linear ligament groove and 

 sometimes a single row of fine denticulations on the hinge margin. While 

 the validity of the genus Paracardium may be regarded as open to ques- 

 tion, it forms at the present a convenience in the nomenclature of these 

 shells. 



Paracardium doris Hall 

 Plate LX, Figs. 13-16 



Cardiola doris Hall, 1783, Pal. of N. Y., vol. v, pt. i, plates and explanations 



70, figs. 10, 11. 

 Paracardium doris Hall, 1885, Ibid., p. 428. 

 Paracardium doris Clarke, 1904, N. Y. State Mus., Mem. vi, p. 304, pi. xi, figs. 



5-10. 



Descripiion. — These shells are small, averaging about the same size 

 as specimens of Bucliiola but are quite regnlarly ovate with the greatest 

 vertical diameter posteriorly. There are from 20-25 simple rounded 

 ribs running from beak to margin, separated by furrows of the same 



