56 CONTRIBUTION TO THE PALEONTOLOGY OF TRINIDAD. 



Meretrix subimpressa var. golfotristensis new variety. Plate IX, Figure 9. 



Description. — A number of shells of a Meretrix were found in bed No. 

 Soldado Rock, which recall the varietal form of Conrad's subimpressa, found by- 

 Professor Harris in the Lignitic Eocene of Wood's Bluff, Alabama. 31 But the 

 Soldado shells when compared with the Museum specimens from Wood's Bluff 

 are seen to be smaller, less convex, more sculptured with concentric lines and 

 with the posterior margin still more prolonged, giving the general outline of the 

 valve a more elliptical form. 



The largest specimen measures in length 20, height 10, thickness of one valve 

 3 mm. 



Locality.— Bed No. 8, Soldado Rock, Gulf of Paria (Golfo Triste of the early 

 navigators) . 



Geological horizon.— Lignitic Eocene. Equivalent to the Lignitic of Alabama. 



Genus PITARIA Rdmer, 1857. 

 Pitaria (Lamelliconcha) circinata Born. Plate IX, Figures 12, 13. 



Venus circinata Born. Test. Mus. Vind.. n. fil. nl. TV fi<r s 17< 



Venus 



Chione 



Quart. Jour. Geol. Soc. London, XXII, p. 582, pi. XXVI 



Jeol. St. Dom., p. 250, 1873. 



circinata Dall, Trans. Wagner Inst. Science, vol. III. p. 1! 



Description.— SheU subequilateral, less trigonal and more circular in outline 

 than is usual in this, group, somewhat compressed; substance thin, rather deli- 

 cate; surface handsomely sculptured with close-set, regular, sharp edged, con- 

 centric lamellae; lunule smaU, narrowly cordate; escutcheon not denned. 



Length of shell 10, height 8.5, diameter 4 mm. 



Remarks.-Except in respect of size this shell is exactly like Dr. Guppy's 

 Cytherea juncea from Cumana, Venezuela. It is no doubt a young specimen .. 

 this very interesting species. Dr. DaU says of P. circinata, "It is one of the 

 very small number of Veneris which occur on both the Atlantic and Pacific 

 coasts of middle America, and in harmony with this exceptional distribution also 



the Isthmian Olig 



This species has remained practically unchanged from Oligocene to recent 



t^V\ltl ah * t0 . the characteristic Lower Oligocene P. imitabilis Conrad 

 from Vicksburg, Mississippi. 



ai/nf ?ST v* ^ "T^ fr ° m the 0H g° cene of Panama (Gatun beds) 



Z^Io(7Zl7! &; f f m the Pli0Cene of Trinidad ; ^d is living on both 



coasts of Central America and in the Antilles 



in S^pS He 8h ° re 100 ° feet M ^ ** at Brighton, Trinidad, 

 Geological horizon. -Upper Oligocene. Equivalent to the Chipolan stage of 





Florida 



Bull 



