CONTRIBUTION TO THE PALEONTOLOGY OF TRINIDAD. 67 



Genus OLIVA Bruguiere, 1789. 

 Oliva trinidadensis new species. Plate X, Figure 4. 



Description. — Shell rather small, characterized by being more pyriform and 

 less cylindrical than is usual in the genus; whorls three, convex; suture deeply 

 impressed, narrowly channelled; base of shell slightly notched; characters of 

 pillar and aperture concealed by the ferruginous matrix. 



Height of shell 15, greatest width 8 mm. 



Remarks. — In its breadth of shoulder and tapering base this species resembles 

 the much larger, recent 0. fusiformis Lamarck, but it is still broader proportionally 

 and widens more suddenly than that shell. 



Dr. Guppy in his list mentions 0. cylindrica Sowerby from the Caroni beds 

 of Trinidad, and 0. reticularis from Jamaica, ispidula and cylindrica from Haiti. 

 The latter Dr. Dall 39 places in synonymy with 0. litterata, and also remarks that 

 ispidula is quite possibly a variety of litterata. 40 



These species are all of a cylindrical outline, quite unlike the shell described 

 above. 



Locality. — Southern main road just south of Pitch L$ke, Brighton, Trinidad. 



Geological horizon. — Upper Oligocene. 



Genus MARGINELLA Lamarck, 1801. 

 Marginella dalliana new species. Plate X, Figures 5, 6. 



Description. — Shell of moderate size, rather solid and strong, subpyriform; 

 whorls four; spire very short, nearly entirely enrolled by the last volution; sides 

 of shell convex; evenly rounded; outer lip in adult specimens much thickened 

 along the margin, not lirate, marked off by an impressed line behind it; aper- 

 ture wide for the genus, especially toward the anterior; inner lip with only a 

 very light callus; columellar plaits four, of which the two anterior are very 

 oblique, the two posterior only slightly so, or nearly horizontal. 



Height of shell 20, greatest breadth 13, length of aperture 18 mm. 



Remarks. — In its general form this species is not unlike Dr. Dall's M . ballista 

 from the Tampa silex beds, of the Florida Oligocene, — only that shell has a 

 decided compression at the central part of the outer lip, and the four columellar 

 plaits all sloping at about the same angle. 



Dr. Guppy's M. coniformis, from the Oligocene of Jamaica and Haiti, is also 

 of somewhat the same form; but is a much slenderer shell with the outer lip 

 slightly lirate, and the aperture much narrower. 



The writer takes great pleasure in naming the Trinidad species in honor of 

 Dr. W. H. Dall of the Smithsonian Institute, Washington, D. C, as a slight 

 token of appreciation of his invariable kindness and helpful suggestions during 

 many years. 



Localities. — Along the shores at Brighton, Trinidad, 1000 feet west of the 

 pier, and also 700 feet east of the pier, in an impure asphalt. 



89 Trans. Wagner Inst., Ill, p. 44. 

 40 Loc. cit., p. 45. 



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