654 E. DeGOLYER 



uplands formed by the rather extensive outHer of Mount Selman 

 beds. To the northeast they extend but a short distance before 

 the flood plain of the Trinity River is reached. 



Though no investigation was made to determine whether or 

 not there are more circular strike-drainage channels concentric to 

 the valley mentioned in this hilly region, the writer strongly 

 suspects that such drainge exists. 



SURFACE GEOLOGY 



The oldest rocks outcropping in the West Point dome are 

 apparently the greenish-yellow clays and shales outcropping in 

 the segment of the inner edge of the central mound lying between the 

 road leading south from Llewellyn Gin and that leading from the 

 Gin to the Lone Star schoolhouse. On a lithologic basis and guided 

 by the apparent relation of these shales to the Wilcox formation, 

 one would refer them to the Midway (Eocene) or Navarro-Taylor 

 (Cretaceous) formations. 



Sidney Powers has collected fossils from these shales or a 

 horizon immediately above them at points respectively i,ooo feet 

 NW.W. and 1,500 feet S.W. of Llewellyn Gin, and their age as 

 published elsewhere' has been determined by Dr. C. Wythe Cook 

 and Dr. L. W. Stephenson, of the United States Geological Survey, 

 as Lower Eocene, either Midway or Wilcox and Upper Cretaceous. 



On these bases the shales are assigned tentatively to the 

 Midway Eocene and Navarro Upper Cretaceous. Dumble's^ state- 

 ment that this dome gives the same section as the Palestine salt 

 dome, in which the outcrops of all of the formations of the Gulf 

 series of the Cretaceous have been recognized, is clearly in error. 

 The writer has seen no evidence of the outcrop, other than that 

 just stated, of any Cretaceous rocks in this dome. 



The center of the dome is covered with the very heavy sandy 

 soil so characteristic of the Wilcox formation. Though not 

 exhaustively searched, no outcrop of the country rock was seen 



' The writer is very much indebted to the kindness of Dr. Powers for permission 

 to use, in the present paper, these fossil determinations which he is discussing in 

 greater detail elsewhere. 



=> E. T. Dumble, op. cit. 



