132 PROCEEDINGS OF THE ACADEMY OF [1895. 



ference between these beds and Lower Claiborne of Alabama. The 

 presence of these lignitic strata in the Texas beds and their absence 

 in Alabama appears to show a difference in the conditions of deposi- 

 tion in the two localities. The lignitic is essentially a marsh pro- 

 duction, while the others belong to a coastal marine, or at least com- 

 paratively shallow sea, and the occurrence of the two in connection 

 with each other would lead to the inference that while a steady 

 marine condition of affairs continued in Alabama, the Texas regions 

 were subjected at irregular intervals to slight oscillations during 

 which the alternate conditions of marsh and sea deposition took 

 place and the presence of marine fossils in the lignitic beds appears 

 to show that these marshes were also subjected to marine influences. 

 The third reason for considering these beds as being synchronous 

 with the Lisbon beds and partly with the green sands of the lower 

 or lignitic beds is their contained fauna. Heilprin states that of 

 some one hundred and forty-five species determined by him about 

 sixty-one, or upwards of forty per cent, are also members of the 

 Claiborne fauna of Alabama, and a few others also occur in some of 

 the older deposits of Alabama. He considers these beds to belong- 

 to the Claibornian or typical Middle Eocene of the gulf slope. 56 

 After the examination of a much more extensive fauna obtained 

 from these beds Mr. Harris arrives at the conclusion that they be- 

 long to the Lisbon sub-stage of the Lower Claiborne. 51 Gabb also 

 arrives at the same conclusion in regard to the fossils found at 

 Wheelock and in Caldwell county, as he says ' ' they are all from a 

 deposit apparently synchronous with that at Claiborne, Alabama ; 

 one-third of the species found in the Texan beds being specifically 

 identical with those found in Alabama." 58 



The identity of the fossils found in the Yegua clays and Fayette 

 sands with those of the Marine beds appears to place these two stages 

 in the same age. 



These beds occupy a wide area of country lying immediately north 

 of the Yegua clays which form their southern boundary, and their 

 northern line may approximately be drawn from the Sabine River 

 a short distance north of Sabine Town in a generally northwestern 

 direction to the middle of the eastern line of Smith County. Turn- 



56 Proceeding of the Academy of Nat. Sci., Phila., Oct., 1890, p. 393. 



" Harris' Monograph of the Texas Tertiary Fossils MSS. 



58 Journal of the Acad, of Nat, Sci., Second Series, Vol. 4, p. 37(i. 



