SUMMARY 475 



similar to the Catahoula of the eastern section. There is a strong uncon- 

 formity between the massive coarse sands of this stage and the overlying 

 thin-bedded sand and clays, which are also palmetto bearing and which 

 we have heretofore classed as belonging to the Oakville. These thin- 

 bedded sands and clays arc overlain unconformably a mile west of La 

 (orange l)y limy clays with calcareous concretions carrying fragments of 

 bone. Tlie section of Town BluJl', or Monument Bluff, one mile east of 

 La Grange, lias already been given. 



On the Kio Grande the only sands recognized are the Fayette and Oak- 

 ville. The fossils of the former, to the southern line of Starr County, 

 ai-e certainly Lower Claiborne. The brown or buff sand between this 

 point and the base of the Frio clays apparently contains no fossils except 

 tlie large oyster, which Harris has determined as 0. alahamienses var. 

 contracia of Conrad, but which was earlier called Ostrea georgiajia. This 

 oyster is also common in smaller form in the beds as far up the river as 

 Carrizo, and the buff sands in which it occurs arc found interstratified 

 with the other fossiliferous sediments. 



Of the few Frio fossils found ])y us there were none characteristic of 

 beds later than the Lower ('lail)oi'ne : hut tliis was also the case with what 

 is noM' regarded as the Jackson, and there is a possibility that when full 

 collections are made from the Frio it may also be classed as Jackson, in 

 which case we will probably have a band of Jackson entirely across the 

 State, showing principally clays on the Sabine and Eio Grande and sands 

 between. 



Our knowledge of the Oakville sands on the Rio Grande is not such as 

 "will permit more definite statements regarding them than have already 

 been made. 



