igo BuLi^ETiN 31 190 



River ; Mt. Lebanon, Winnfield (1000 feet deep in well), La. 

 Near Enterprise, Miss. 



Corbula texana Gabb, PI. 57, Figs. 24-28 



C. texana Gabb, Jour. Phila. Acad. Nat. Sci., 2d Ser. , vol. 4, p. 386, 



pi. 67, fig. 54- 

 C. texana Dall, Trans. Wag., Ill, pt. 4, p. 845, 1898. 



Gabb' s original description. — Inflated, subtriangnlar, thick, umbones 

 large ; right valve marked by numerous large transverse ribs ; umbonal 

 slopes rather abrupt ; basal margin regularly rounded ; left valve ? 



Dimensions. — Length .3 in., width .38 in., depth of right valve .15 in. 

 Common. I have seen numerous specimens of the right valve but none 

 of the left. 



The left valve is considerably smaller than the right, nearly 

 smooth ; long-quadrangular in outline ; marked by two or some- 

 times three folds radiating from the beak. 



This species seems but distantly related to any other Amer- 

 ican Eocene type. A few of its markings recall nmrchisoni, but 

 it is only half the dimensions of that species, its right valve has 

 nothing of the characteristic, even lirations of the latter having 

 only fine lines and great irregular breaks in the exterior surface. 

 Both valves are very much shallower than in murcJiisoni. On 

 the left valve, however, there are very distinct radiating folds : 

 on niurchisoni these must be viewed in the right light, oftentimes, 

 in order to be seen at all. This is preeminently a Texan Mid- 

 Eocene form flourishing in the midst of the richest molluscan 

 faunas. 



Corbula rugosa Lam., of the Paris Basin resembles this, 

 somewhat, but is more regular in surface markings, more nasute 

 posteriorly, and larger. 



Type. — Lost. Duplicates in Phila. Acad. Mus. 



Horizo7i. — St. Maurice Eocene. 



Specimens figured. — Paleont. Mus. Cornell Univ. 



Localities. — Mosley's Ferry and Cedar Cr., Burleson Co. ; 

 A. Kimble headright, Cherokee Co. ; Sabine river, opp. S. 35, 

 5N., 13 W. 



