135 MOLIvUSCA OF THE Gui.F OF MFXICO 103 



Genus RANGIA Desmoulins 



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

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

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

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

 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. I^in. de Bordeaux, 5, ] 

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

 p. 232, '61. 



grayi Tuomey and Holmes, Pleio. Fos. S. C, p. 99> pl- 

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



nmior Holmes, Post-Pl. Fos. S. C, p. 41, i860. Not of 

 Conrad 1840=^^?. clathrodon 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. i), 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. I 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. i, 784 



