474 E. T. DUMBLE PROBLEM OF TEXAS TERTIARY SANDS 



by Hager, between the Catahoula and the overlying Burkeville stage of 

 the Fleming. 



In the area between the Sabine and Trinity the Fayette, if it occurs at 

 all, is represented by remnantal patches. 



In the Trinity Eiver section the Fayette and Frio appear to be want- 

 ing ; but in the Jackson the clays which were predominant on the Sabine 

 have largely given place to sand, so that we have here the Jackson sands 

 overlain by the Corrigan, which, apparently, graduates into the Fleming 

 through a series of interbedded clays and sands. The Oakville is prob- 

 ably represented on the Trinity by some part of the Fleming clays. 



On the Navasota the Jackson sands (Wellborn ?-Manning) are fol- 

 lowed by the Corrigan, and the basal portion of the succeeding Fleming 

 is composed largely of sands, so that we have three formations in which 

 sand is predominant succeeding one another. The presence of Fayette 

 in this section has not been proven, nor has the Oakville certainly been 

 differentiated from the Fleming. 



In our earlier work it was considered that the occurrence of opalized 

 wood was characteristic of the Fayette only. East of the Brazos, where 

 the Fayette is lacking, it is found in the Corrigan beds only. If it be 

 representative of the Corrigan rather than of the Fayette, it would change 

 the reference of our beds near Nails Creek, in Lee Count}^, and near 

 Ledbetter, from Fayette to Corrigan. 



On the Colorado the section as previously understood will require re- 

 vision. No determinable fossils other than plants have been found east 

 of AMiite Marl Bluff, and it will require more detailed work than has yet 

 been done to decide the exact correlation of the various beds occurring 

 here. 



White Marl Bluff, just west of the Bastrop-Fayette line, carries a 

 fauna which is distinctly that of the Marine beds. The Yegua, beginning 

 at the county line and continuing to near AVest Point, shows the charac- 

 teristic dark clays, sands, and lignites of that substage, with their limonite 

 concretions. These beds are followed, in the two exposures noted by Pen- 

 rose as "Chalk bluffs," by the typical light-colored sands and clays of his 

 Fayette beds. Some of the hard, gray sandstones connected with these 

 are seen just south of West Point. A series of darker colored lignitic 

 sands and clays, which are exposed from the vicinity of Ptabbs Creek east- 

 ward to the base of Palm Bluff, some three miles from La Grange, may 

 represent the Jackson in this section. It includes the heavy lignite beds 

 at Mantons Bluff. Overlying these, in Palm Bluff, there is a series of 

 sands and clays and quartzites, with opalized wood and palmetto, which 

 we have heretofore included in the Fayette, but which is lithologically 



