MARYLAND GEOLOGICAL SURVEY 669 



2 mm. in length, their distance apart being about equal to the space 

 occupied by two costas; the two intervening interspaces are occupied by 

 rows of much smaller tubercles a little compressed laterally, situated at 

 intervals about one-third the distance between the spines in each row. 

 On the anterior and posterior slopes of the shell several rows of spines 

 alternate with single rows of tubercles. The longest spines occur upon the 

 posterior cardinal slope." Weller, 1907. 



The species is represented in Maryland chiefly by casts of the interior, 

 although a few fragments of the exterior surface have been preserved 

 both in the form of casts and of the original shell. The casts are isloated 

 from those of C. kummeli and C. tenuistriatum Whitfield by their rela- 

 tively broader, more globose and much more nearly equilateral outline. 

 It is by far the most abundant of the three species within the area under 

 discussion. 



Occurrence. MATAWAN FORMATION. ? Post 105, Chesapeake and 

 Delaware Canal, Delaware. MONMOUTH FORMATION. Brightseat, 

 Brooks estate near Seat Pleasant, 2 miles southwest of Oxon Hill, Prince 

 George's County, Maryland. 



Collections. Maryland Geological Survey, Philadelphia Academy of 

 Natural Sciences, U. S. National Museum. 



Outside Distribution. Matawan Formation. Woodbury clay, Weno- 

 nah sand, New Jersey. Monmouth Formation. Eed Bank sand, New 

 Jersey. Eutaw Formation (Tombigbee sand member). Exogyra pon~ 

 derosa zone, Prentiss County, Mississippi. Ripley Formation. Exogyra 

 costata zone, Union and Tippah counties, Mississippi. 



CARDIUM TENUISTRIATUM (Whitfield) Weller 



Cardium eufalensis Whitfield, 1885, Mon. U. S. Geol. Survey, vol. ix, p. 132, 



pi. xx, figs. 18, 19 (not fig. 17). (Not C. eufalense Conrad, 1860.) 

 Cardium (Criocardium) dumosum Whitfield, 1885, Ibidem, p. 133, pi. xx, 



figs. 10-12 (not figs. 9 and ? 13). (Not C. dumosum Conrad, 1870.) 

 Cardium (Criocardium) multiradiatum Whitfield, 1885, Ibidem, p. 135, pi. 



xxi, figs. 1-3. (Not C. multiradiatum Gabb, 1860.) 



Fragum tenuistriatum Whitfield, 1885, Ibidem, p. 139, pi. xx, figs. 15, 16. 

 Cardium tenuistriatum Weller, 1907, Geol. Survey of New Jersey, Pal., vol. 



iv, p. 591, pi. Ixv, figs. 13-19. 



