39 Mollusca of the Gulf of Mexico 7 



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

 iana ; Galveston. 

 Pleistocene : Grand Chenier, New Orleans Gymnasium well at 

 1200 feet, Lake Borgne borings, Knapp's wells, Terre- 

 bonne Parish, No. 1 at 1600- 1700, No. 2 at 1050- 1 190, 

 1519-1542, 1552-1632, No. 3 at 57°-7°°> io 43, 1150- 1200 , 

 1200-1300 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., 1st. ser., vol. 4, p. 



141, pi. 10, fig. 6, 1824. (Not Nitcula concentrica Fischer, 



Fos. Moscow, 1843). 

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



p. 24, pi. 1, fig. 4, 1846. 

 Leda 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. 1, No. 3, p. 89, 1895 ; 



Dall, Trans. Wag. Inst. Sci., vol. 3, pt. 4, p. 588, 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. Sci., vol. 3, pt. 4, p. 589, pi. 32, 

 fig. 6, 1898. 



Closely related to the recent Leda acuta Conrad, but differing 

 in details of sculpture. 



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

 ida ; Bascom No. 1 well, near Mobile, Alabama, at 1500- 

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



