lOi St. Maurice and Claiborne Pelecypoda ioi 



the nepioiiic sculpture, which in C. protfxfus extends over a radius on the 

 disk of some eight or ten millimeters. The latter also has more conspicuous 

 radial striation and coarser crenulations. 



Eocene of Wautubbee hills, Clark County, Mississippi, Burns; near 

 Saline Bayou, St. Maurice, Louisiana, Vaughan ; and at Claiborne, Ala- 

 bama, L. C. Johnson. 



At the localities designated above by Dall one finds a great 

 variation in form, size and surface markings in this type of 

 Crassatcllitcs. The short, smooth forms with rather marked 

 carina and few umbonal undulations as indicated by Ball's fig- 

 ures may be called clarkensis, s. s. They are common at St. 

 Maurice, La. With these at St. Maurice and near Enterprise, 

 Miss., are similar forms with rather fine and extensively dis- 

 played concentric marking; these may receive the varietal name 

 of ludoviciauKS. Again, to the east in Alabama and especially' in 

 South Carolina the "nepionic concentric ridges" of clarkensis are 

 extended over considerable of the umbonal area as shown by pi. 

 34, fig. 7 and the "marked carina" maj^ become less obvious as 

 in fig. 9 of the same jilate. Here, too, the posterior ma3' or ma}" 

 not be "pointed". These long specimens, showing oftentimes 

 so much umbonal liration and giving almost a hint at a distant 

 relationship with alcsformis, may receive the varietal name of 

 ferrocarolin us. 



Type of clarkensis. — U. S. Nat. Mus. 



Horizon. — St. Maurice Eocene. 



Specimens figtired. — Paleont. Mus. Cornell Univ. 



Loclities. — Rio Grande, i mile above Starr-Zapata Co. line, 

 Tex. ; 3 miles S. E. of Negreet, St. Maurice, Chautauqua, Rob- 

 ertsville ; Cooper's well, Winnfield, La., looo ft. ; 2^^ miles 

 E. of Newton, Wautubbee, 8 miles W. of Enterprise, Miss. ; 

 Lisbon, base of bluff at Claiborne, Ala. ; 3 miles W. N. W. of 

 Orangeburg, S. C. 



Crassatellites protextus Con., PI. 35. Figs. 1-5. 



Crassatella protexta Con, Foss. Sh. Tert. Form., 1832, p. 22, pi. 8, 



fig. 2. 

 Crassatella protexta de Greg., Mon Faun. Eoc. Ala., 1890, p. 198, 



