CONTRIBUTION TO THE PALEONTOLOGY OF TRINIDAD. 51 



from Soldado Rock, which match exactly small specimens of V. alticostata in 

 the Paleontological Museum of Cornell University from the Lignitic Eocene of 

 Woods Bluff, Alabama. They answer perfectly to Conrad's description and 

 show the characteristic carinating line on the anterior side of the ribs. 



This species has also been found in the Midway of Texas and Alabama by 

 Professor Harris. At the very base of the Midway beds at Snow Hill, Alabama, 

 he has found a very small ancestral form, about one centimeter in length. Higher 

 up in the beds the shell assumes a larger size and more typical aspect. The 

 Soldado shells measure about 15 mm. in width. This species was less abundant 

 there than V. planicosta. 



Locality .—Bed No. 2, Soldado Rock, Gulf of Paria. 

 Geological horizon. — Midway Eocene. 



Venericardia crucedemaionis new species. Plate VIII, Figure 14. 



Description. — Shell small, cordate; substance thin and fragile; sculpture of 

 (a) very narrow, elevated, radial riblets with much wider interspaces; riblets 

 squamose at the posterior end of the valve and nodular-stellate over the central 

 portion; (6) interradial striae, one on each side of the basal part of the riblets 

 at the anterior part of the shell; but entirely absent from the posterior end of 

 the shell; characters of hinge concealed by the matrix. 



Height of shell 6, length of portion exposed 7 mm. 



Remarks. — This species is evidently closely related to V. alticostata Conrad, 

 but differs in having two interradial striae, one at the base of each side of the 

 anterior riblets while alticostata has only one. This is also a much smaller and 

 more delicate shell than Conrad's species. 



It may be that if more specimens of Venericardias of the alticostata group are 

 ever obtained from Soldado Rock, this species and the larger form, that the 

 writer has described as V. thalassoplekta , may be found to be both strongly 

 marked varieties of V. alticostata. In the material we have now, there are three 

 forms — one which, though very small, answers perfectly in sculpture to Conrad's 

 description of alticostata; the species described above; third, the larger form, V, 

 thalassoplekta. Tentatively the two last mentioned are described as separate 

 species. A shell varying in a similar direction from planicosta is figured by 

 Professor Harris from the Lignitic of Alabama. 27 



Locality.— Bed No. 8, Soldado Rock, Gulf of Paria. 



Geological horizon.-— Lignitic Eocene. Equivalent to that of Alabama. 



The specific name is given because of the shell's starry nodules. The Southern 

 Cross in Venezuela is called Cruce de Maio, since in the month of May it attains 

 its greatest splendor. 



Venericardia planicosta Lamarck. Plate VIII, Figures 15, 16. 



Vv- l /""*'* "'"on* uauiaitn, oyai. ties An. s. vert., p. l^so, ioui, s\uu. uu 



^ IX, pi. 31, fig. 10. 

 Venericardia (planicosta) Lamarck, Ann. du Mus.. vol. IX. pi. 31. fies. 10, a, b 



Mus 



J7 



Bull. Am 



