466 E. T. DUMBLE PROBLEM OF TEXAS TERTIARY SANDS 



The Corrigan comprises coarse "rice" ^^ sands and sandstones at the 

 base, overlain by finer sands and by yellowish green clay and claystones 

 with plant remains. The clays and claystones carry pyritic nodules and 

 streaks of lignite and weather yellow to cream color. The sands are 

 coarse to fine-grained and may be friable, cemented Avith opaline or por- 

 celaneoiis matter, or hardened to a dense gray-ljlue quartzite. There are 

 local unconformities between the sands and clays and the sands often 

 carry clay balls and are occasionally cross-bedded. Volcanic ash is rare 

 in them. They are noted for the abundance of fossil palms, and the fossil 

 wood which occurs in them is often opalized. 



On the Santa Fe, in Jasper County, the contact of the Corrigan and 

 Jackson is found just south of Brookeland, and it passes under the Flem- 

 ing about 5 miles north of the Jasper. Many excellent exposures are 

 found along the Angelina and the ISTeches rivers west of this. On the 

 Texas & New Orleans Eailroad the outcrop, as determined by Baker and 

 Suman, has a width of 5 miles, with Rockland as its center. In the Cor- 

 rigan section, which begins one mile north of Corrigan and extends south- 

 ward to Moscow, we find these materials tyi^ically displayed, and in con- 

 nection with them local conglomerates occur. A\itli i)ebbles of jasper, flint, 

 and quartz up to mi iiidi in diameter. Palm leaves are abundant also. 



In the exposures of the Trinity Eiver region, while the basal beds are 

 the same as those to the eastward, there appears to be at the top a tran- 

 sitional zone, in which sands of the Corrigan are interbedded with cal- 

 careous clays similar to those of the overlying Fleming. On this account 

 the limit is not as well defined as further east, and the upper line is 

 drawn where the sands with porcelaneous cement cease and the clays 

 weather entirely dark brown or black, instead of showing the character- 

 istic yellow weathering of the Corrigan clays. 



These upper beds maintain their character and thickness as far west as 

 the Navasota Eiver. While they appear to be later than the Catahoula 

 ]H'oper, they are definitely connected Avith it by the character of the sands 

 and clays of which they are composed. 



For this portion of the Corrigan the name Onalaska is proposed, from 

 the name of a town in Polk Coimty which is located on them. Excellent 

 exposures may be found on Kickapoo Creek east of the town and on 

 Harmon Creek northeast of Huntsville. 



On the Trinity & Brazos Valley Railway, in Grimes County, the Jack- 

 son-Corrigan contact was found about 21/2 miles south of Singleton and 

 the Corrigan-Fleming contact just north of Eichards. 



Although two or three fragments of bone were found in the sands, no 



' So caHed because of the resemblance of the grains to those of rice. 



