402 GEOLOGY OF NORTHWESTERN TEXAS. 



Towards the top the sandstones become more shaly and the clays more 

 sandy. There are also some beds of gypsum, but not in such great abund- 

 ance as is found in the Double Mountain Beds. These beds lie conformably, 

 or nearly so, upon the Albany Beds of the Coal Measures. They appear to 

 be entirely conformable, and might be taken as one continuous bed of sedi- 

 mentation, were it not that the position of the Wichita Beds is between them, 

 and, as we have seen elsewhere, these Wichita Beds are two thousand feet 

 thick, so a considerable lapse of time must have intervened between the 

 times of their deposition. 



DOUBLE MOUNTAIN BEDS. 



These beds lie directly in contact with the Clear Fork Beds throughout 

 the whole length, and no attempt has been made to determine a definite line 

 of division between the two divisions. The beds are composed of sandstones, 

 limestones, sandy shales, red and bluish clays, and thick beds of gypsum. 

 The limestones are generally of an earthy variety, and in places have many 

 casts of fossils, the newer types being more largely represented than those of 

 the older. The gypsum beds are numerous and many of them very thick. 

 All the clays and shales are impregnated with gypsum, and many of them 

 carry a large per cent of common salt. 



The sandstones are generally very friable, and are of various colors, red, 

 white, and spotted. 



The strata have a very uniform dip to the northwest until near their west- 

 ern border, where they are much distorted and crumpled, as though there had 

 been a heavy pressure from the northwestward, compressing the strata into 

 short folds. These beds have a thickness of about nineteen hundred feet. 

 Toward the western extremity of the beds the red clays are transected in every 

 direction with seams of fibrous gypsum, making a perfect network. These 

 seams of gypsum range in thickness from that of a sheet of paper to ten 

 inches. 



THE SECTION. 



The following sections, the line and localities of which are given on the 

 accompanying map, were made of the Wichita Beds along the south side of 

 the Big Wichita River, beginning four miles west of the east line of Baylor 

 County: 



SECTION NO. 28, WICHITA BEDS. 



1. Red clay 30 feet. 



2. Limestone 2 feet. 



3. Blue clay 4 feet. 



4. Limestone 1 foot. 



Total , 3 1 feet, 



