190 PERMIAN OF TEXAS AND ITS OVERLYING BEDS. 



relation. I have found everywhere on the beds of the Permian belt pieces 

 of conglomerate and large pebbles of white quartz that did not belong to the 

 Trinity sands of the Cretaceous which were supposed to overlie the Permian 

 to the westward, and it is a matter of interest to know where this drift came 

 from. The fragments of conglomerate increased in size as we traveled west- 

 ward until we came upon the beds of that material in the vicinity of Dockum, 

 and the question was solved as to the origin of the fragments of conglomer- 

 ate and the quartz pebbles. 



In the conglomerate are many silicified trunks of trees, some of them of 

 great length. In the red clay above the conglomerate are fossil remains of 

 large reptiles, whose species I was unable to determine in the field. In the 

 upper sandstone were many casts of a Ohio that I have provisionally called 

 Onto documensis. In most places that fossil occurs only as casts, and in one 

 place only did I find specimens of both valves, and they were so badly in- 

 crusted with carbonate of lime that the peculiar markings of the shell could 

 not be seen. The sandstone was everywhere full of scales of mica, some of 

 the scales being one-sixteenth of an inch square. The whole thickness of 

 this formation in this vicinity is about 150 feet. These beds extend under 

 the Staked Plains. I traced them up Blanco Canyon to the falls of White 

 River, where they pass out of sight under the beds of the overlying strata. 



There are a great many springs of clear pure water flowing from these 

 beds, and wherever the formation has been penetrated by wells, an abundance 

 of good water has been obtained. 



BLANCO CANYON BEDS. 



Overlaying and resting unconformably upon the Dockum Beds are beds of 

 red clay, white sandy clays, white clays, and a hardened clayey limestone, 

 fronting to the eastward and forming bold escarpments 200 feet high. These 

 beds constitute the Staked Plains. Because of the extensive presentation of 

 these strata in Blanco Canyon, Dickens County, I have given them the name of 

 Blanco Canyon Beds. The strata have a very slight dip to the southeast. A 

 distance of twenty-five miles gave an average dip of eight feet to the mile. 

 The surface is almost level, except where it is traversed by deep canyons. 

 These canyons occur only at wide distances. 



The only fossils found in these beds were some of the larger mammals and 

 a species of turtle. Enough was found to show the strata to be of much 

 more recent date than the Cretaceous which is found at the foot of the Staked 

 Plains farther southward. Blanco Canyon takes its name from a butte on 

 the west side of the canyon, twenty miles from its mouth, which is capped 

 with a white clay with the appearance of chalk. White River, a beautiful 

 stream of clear water, flows through the canyon, fed by numerous bold springs 



