63 St. Maurice and Claiborne Pelecypoda 63 



of the shell is thick, and it is suspected that when found perfect, it will 

 prove to be the largest species yet described. This fragment certainly war- 

 rants such a conclusion. 



Since Lea'.= time Cossmann and Aldrich have found frag- 

 ments of this species in the Claiborne sands. Two fragments 

 from the latter' s collections we have herewith figured. Very 

 likely Aldrich' s lisbotiensis should be referred to a variety of this 

 species as the markings agree exactly. It would appear, how- 

 ever, that the Claiborne specimens are not so elongated as those 

 from the St. Maurice stage. 



Type. — Phila. Acad., Lea Coll., No. 5996. 



Horizon. — Claiborne sand. 



Leda magna, var. lisbonensis Aldrich, PI. 24. Figs. 5-7. 



L. lisbonensis Aldr., Bull. Amer. Pal., vol. i, 1895, p. 69. pi. 6, fig. 4. 



For the original characterization, see the above reference. 



Type. — Aldrich Coll., John Hopkins Univ. 



Horizon. — St. Maurice Eocene. 



Specimens figured. — From Lisbon, deposited in the Paleont. 

 Mus. Cornell Univ. 



Localities. — St. Augustine, Tex. ; 200 3'ds. below the mouth 

 of Negreet Bayou ; 3 miles S. E. of Negreet P. O. ; Monroe 

 well, 1200 ft., La. ; St. Maurice road, i mile S. W. of Winnfield 

 Marble Q'y, La. ; Lisbon and Hamilton Bluff, Ala. ; 27 miles 

 above Newburn ; Ft. Gaines, Ga., ? Neuse River, between 16 

 and 17 miles above Newburn, N. C. 



At the last mentioned locality a few large casts have been 

 collected perhaps belonging to this species, but their character- 

 istics are not obvious. Lisbon seems to be the place where this 

 species is best exhibited. The Texas and Louisiana specimens 

 so far found are much smaller than the Lisbon types. They show 

 a slightly curved rib on the escutcheon area more plainly than do 

 those from Lisbon, but the characteristic, very oblique striation 

 over this area they exhibit very indifferently. 



