135 MOI^USCA OF THE Gui^F OF MEXICO 103 



Genus RAMGIA Desmoulins 



cuneata Gray, In Sowerby, Gen. Shells, No. 36, f. 1-7, 1831, (as 

 Gnathodon); Holmes, Post-Pi. Fos. S. C, p. 41, pi. 7, f. 

 10, '60 ; Hilgard, House Rep. Ex. Doc. 1, pt. 2, p. 887, 

 '78 ; Dall, Bull. 37, U. S. N. M., p. 62, '89 ; Singley, 4th 

 Ann. Rept. Tex., p. 329, '92 ; Dall, Proc. U. S. N. M., 17, 

 P- 97, '94; Nautilus, 8, p. 27, '94; Tr. W. I. S., 3, p. 

 904, '98. 



cyrenoides Desmoulins, Actes Soc. Lin. de Bordeaux, 5, p. 

 57, f. 1-3, 1832 ; Conrad, Proc. Acad. Nat. Sci. Phila., 1., 

 p. 232, '61. 



grayi Tuomey and Holmes, Pleio. Fos. S. C, p. 99, pi. 



23, f. 11, 1857. Not of Conrad. 

 minor Holmes, Post-Pi. Fos. S. C, p. 41, i860. Not of 

 Conrad 1840=^?. clathrodoii Con. 



Note. — Often referred to Gnathodon Gray, 1831, preoccupied 

 by Goldfuss, 1820 (fish genus). This species is the geno- 

 type. Rangia is peculiar to North America. In Louis- 

 iana R. cuneata extends up streams into freshwater for 

 several miles. Extremely abundant in Pleistocene time 

 as shown by shell banks underlying Mobile and Charles- 

 ton. In Pleistocene range extended north to Cornfield 

 Harbor, Md., at the mouth of Potomac River. Extreme- 

 ly common iu the Gulf State wells, extending to a depth 

 of 2106 feet, (Teche No. 1), and not infrequently associ- 

 ated with R.johnsoni. 



Distribution. — West Florida to Vera Cruz. Pascagoula Mio- 

 cene to Recent. Gulf coast. — St Mark's, Ft. Barranca, 

 Fla. ; Mobile Bay, Ala. ; Belle Isle, Point au Fer, Cam- 

 eron, Lake Charles, La. ; Matagorda Bay, Nueces River, 

 etc., Texas. Pleistocene : Grand Chenier, New Orleans 

 pumping station No. 7 ; Knapp's wells, Terrebonne Par- 

 ish, No. 1 at 2000-2150, No. 2, from 1050 to 1842, No. 3, 

 surface to 1800 feet ; Bayou City well, Beaumont, Texas, 

 600 feet. Pliocene : Caloosahatchie, Fla. Pleistocene 

 and Upper Miocene : Jennings wells, Franklin No. 1, 784 



