MARYLAND GEOLOGICAL SURVEY 277 



rior portion not or but slightly expanded; posterior not or bnt slightly 

 contracted and produced; surface with irregular, concentric undula- 

 tions, more or less strongly marked and sometimes lamellar. 



It differs from P. goldfussii Wagner in being more equilateral, less 

 expanded anteriorly and less contracted and produced posteriorly. 



Length, 90 mm.; height, 51 mm.; diameter, 8 mm. 



Occurrence. — Choptank Formatiox. Governor Eun (lower bed). 

 Calvert Formation. Plum Point, Lyon's Creek, AVhite's Landing, 

 Wye Mills, Fairhaven, N^ew Town (?). 



Collections. — Maryland Geological Survey, Johns Hopkins University, 

 U. S. National Museum. 



Panopea goldfussii Wagner. 

 Plate LXVI, Fig. 1. 



Panopea Goldfussii Wagner, 1839, Jour. Acad. Nat. Sci. Phila., voL viii, 1st sen, 



p. 52, pi. i, fig. 3. Probably published privately in 1838. 

 Panopcea porrecta Conrad, 1843, Fossils of tlie Medial Tertiary, p. 71, pi. xli, fig. 2. 

 Glycinieris Goldfussii Conrad, I860, Proc. Acad. Nat. Sci. Phila., vol. xiv, p. 571. 

 Panopcea Goldfussii Meek, 1864, Miocene Checlv List, Smith. Misc. Coll. (183), p. 13. 

 Panopcea porrecta Meek, 1864, Miocene Check List, Smith. Misc. Coll. (183), p. 13. 

 Panopea Golclfitssii Dall, 1898, Trans. Wagner Free Inst. Sci., vol. iii, pt. iv. p. 829. 



Description. — " Shell oblong, subovate, ventricose; disks with con- 

 centric, unequal, shallow grooves; lines of growth coarse and prominent; 

 anterior extremity slightly gaping; anterior margin rounded, anterior 

 dorsal margin elevated; posterior side narrowed, somewhat produced, 

 not reflected; posterior dorsal margin nearly rectilinear; cardinal teeth 

 obliquely compressed, united at base to the nympha, short and not 

 very prominent." Wagner, 1839. 



Length, 117 mm.; height, 58 mm.; diameter, 31 mm. 



Occurrence. — St. Mary's Formation. Cove Point, St. Mary's Eiver, 

 Choptank Formation. Governor Eun (lower bed), Joues Wharf, Paw- 

 paw Point. Calvert Formation. Plum Point, Wye Mills, New 

 Town(?). 



Collections. — Maryland Geological Survey, Johns Hopkins University, 

 U. S. National Museum. 



