1890.] NATURAL SCIENCES OF PHILADELPHIA. 393 



THE EOCENE MOLLUSCA OF THE STATE OF TEXAS. 

 BY PROFESSOR ANGELO HEILPRIN. 



The following list embraces, so far as I know, all the Eocene Mol- 

 liisca that have thus far been noted to occur in the Gulf deposits of 

 the State of Texas. For my data I have used the type series of Gabb 

 and Conrad, the major portion of which is in the possession of the 

 Academy of Natural Sciences of Philadelphia, the extensive collection 

 of the State Geological Survey, and minor collections which have from 

 time to time reached the Academy and been reported upon in 

 its publications. The collections of the State Geological Survey 

 (for the use of which I am indebted to the Director, Mr. E. T. 

 Dumble, and to Dr. R. A. F. Penrose, Jr., the geologist of the Ter- 

 tiary areas of the State) are by far the most extensive, and they 

 serve to definitely locate the formations whence the fossils were ob- 

 tained in their true position in the geological scale. Of some 145, 

 species here enumerated (including a few doubtfully determined 

 forms) about 61 (or upwards of 40 per cent.) are also members of 

 the Claiborne fauna of Alabama ; these I have indicated by prefix- 

 ing an asterisk. A few others occur in some of the older deposits 

 of Alabama, while a very few are members of the Mississippi (newer) 

 fauna. The recurrence of a large number of the species in various 

 counties and localities indicates that the horizon is a common one, 

 namely : the Claibornian, or typical Middle Eocene of the Gulf slope, 

 the equivalent of the Calcaire Grossier of the Paris Basin. 



The principal localities whence the fossils were obtained are : Cher- 

 okee Co., near Alto and McBee's School ; Palestine, in Anderson Co. ; 

 Robertson Co., near Wheelock ; Milam Bluff in Milam Co. ; Burleson 

 Shell Bluff in Burleson Co. ; Smithville, Devil's Eye, Bombshell 

 Blufi'and "Camp Disaster," in Bastrop Co. ; Caldwell Co.; Atas- 

 cosa Co. ; Laredo, in Webb Co. ; and Stations 1-5 on the Rio 

 Grande River, included between Carrizo and " Cardita Bluff," in 

 the northwestern corner of Webb Co. 



In my references to Conrad's descriptions I have intentionally 

 referred in some cases to the first edition of the " Fossil Shells of the 

 Tertiary Formations" (abridged F. S. T.), and in others by prefer- 

 ence to the second edition, where many of the forms are more com- 

 pletely diagnosed or illustrated than in the original edition. 



