722 SYSTEMATIC PALEONTOLOGY 



" The internal features of the species are not easily made out from the 

 imperfect casts under examination, the shell having been too fragile to 

 leave the impressions of pallial line or muscular scars so as to be traced 

 with any degree of certainty. The hinge, however, has been considerably 

 thickened and has left the imprint of its features on some of the speci- 

 mens, so that by the use of gutta-percha its features have been fairly 

 shown. There is positive evidence of only a single projecting tooth in each 

 valve, which has been long and incurved." Whitfield, 1885. 



The shell is represented in the area under discussion only by a single 

 cast collected from along the canal, one of Conrad's original localities. 



It differs from Panope monmouthensis in the more compressed valves, 

 the more prominent and more anterior umbones and the more oblique 

 anterior dorsal margin. 



Occurrence. MATAWAN FORMATION. Post 105, Chesapeake and Dela- 

 ware Canal, Delaware. 



Collections. Maryland Geological Survey, Philadelphia Academy of 

 Natural Sciences, New Jersey Geological Survey, U. S. National Museum. 



Outside Distribution. Matawan Formation. Merchantville clay marl, 

 Woodbury clay, Wenonah sand, New Jersey. 31onmouth Formation. 

 Navesink marl, Eed Bank sand, New Jersey. Peedee Formation. North 

 and South Carolina. Eutaw Formation (Tombigbee sand member). 

 Exogyra ponderosa zone, Prentiss County, Mississippi. Eipley Formation. 

 Exogyra costata zone, Warrior County, Georgia; Owl Creek, Tippah 

 County, Mississippi. 



PANOPE MONMOUTHENSIS n. sp. 

 Plate XLV, Figs. 4, 5 



Description. Shell large, subcylindrical in outline, inequilateral, gap- 

 ing posteriorly, apparently closed in front; umbones subcentral, not very 

 prominent; dorsal margins straight; anterior lateral margin broadly 

 rounded, or obscurely truncate, posterior obliquely truncate from the dor- 

 sal margin to the ventral so that the former margin is more produced pos- 

 teriorly than the latter; base line approximately straight and parallel to 



