39 MOLLUSCA OF THE GuLF OF MEXICO 



Crooked Island, Florida ; Point au Fer, Cameron, Louis- 

 iana ; Galveston. 



Pleistocene : Grand Chenier, New Orleans Gymnasium well at 

 1 200 feet. Lake Borgne borings, Knapp's wells, Terre- 

 bonne Parish, No. i at 1600-1700, No. 2 at 1050-1190, 

 1519-1542, 1552-1632, No. 3 at 570-700, 1043, 1 150-1200, 

 1 200- 1300 feet, Bayou City Oil Co.'s well, Texas, at 600 

 feet. 



Miocene: Bascom No. 2 well, near Mobile, Alabama, at 1800 



feet. 



COncentrica Say, Jour. Acad. Nat. Sci., Phila., ist. ser., vol. 4, p. 



141, pi. 10, fig. 6, 1824. (^ot N'uada concentricaV\sc\\er, 



Fos. Moscow, 1843). 



Nucula eborea Conrad, Proc. Acad. Nat. Sci. Phila., vol. 3, 



p. 24, pi. I, fig. 4, 1846. 

 Lcda eborea Dall, Proc. U. S. Nat. Mus., vol. 6, p. 341, 



1883. 

 concentrica Dall, Bull. 37, U. S. Nat. Mus., p. 44, 1889; 

 Singley, Fourth Ann. Rept. Geol. Surv. Texas, p. 326, 

 1892 ; Harris, Bull. Am. Pal., vol. i, No. 3, p. 89, 1895 ; 

 Dall, Trans. Wag. Inst. Sci., vol. 3, pt. 4, p. 58S, 1898 ; 

 Mitchell, List Marine Shells Texas. 



Distribution. — Texas to Trinidad. Upper Miocene to Recent. 



Gulf Coast. — Recent : Cedar Keys, Galveston, Corpus Christi. 

 Tampa was Conrad's type locality of eborea. 



Pleistocene : Gulf Coast (Dall). Upper Miocene : Galveston 

 artesian well ranging from the surface to 2650 feet 

 (Harris). 



dodona Dall, Trans. Wag. Inst. vSci., vol. 3, pt. 4, p. 589, pi. 32, 

 fig. 6, 1898. 



Clo.sely related to the recent Leda acuta Conrad, but differing 

 in details of sculpture. 



Distribution. — Miocene, Oak Grove, Santa Rosa County, Flor- 

 ida ; Bascom No. i well, near Mobile, Alabama, at 1500- 

 1556 feet. Oak Grove horizon. Aldrich's collection. 



