TRIASSIC. 425 



the State of the fossil wood so abundant east of the plains, and should evi- 

 dently be placed at a different horizon. 



The beds that I designated under the provisional name of Dockum Beds 

 are so similar to the Shinarump Beds, as described in "Geology of the High 

 Plateaus," by Powell, that I here give an extract from that report, page 147: 



"Within these shales there often appears a singular conglomerate. It con- 

 sists of fragments of silicified wood embedded in a matrix of sand and gravel. 

 Sometimes trunks of trees of considerable size thoroughly silicified are found, 

 to which the Piute Indians have given the name 'Shinarump,' meaning the 

 weapons of Shinav, the Wolf G-od." 



Again, Mr. C. E. Dutton says: "Whenever we encounter a cliff which 

 discloses the upper Permian Beds we find at the summit of the escarpment a 

 band of pale brown sandstone of very coarse texture, often becoming a con- 

 glomerate. Its thickness is usually from forty to seventy-five feet."* 



This conglomerate was found in that region resting upon strata known to 

 be Permian, but there was no break in the deposit and the exact line of de- 

 marcation between the Permian below and the Triassic above had never been 

 determined. Such, however, is not the case with the beds in this locality 

 The dip of the Permian is to the northwest, while these beds dip to the south 

 east, in the same direction as that of the Cretaceous further to the southward 



The thickness of these beds in the vicinity of Dockum is about one hun 

 dred and fifty feet. Of this about ten feet is made up of this peculiar con 

 glomerate. At places, however, this conglomerate is over fifty feet thick. 



The following section was made about three miles north of Dockum. Be- 

 ginning at the bottom: 



1. Red Clay 20 feet. 



2. Sandstone, cross-bedded 10 feet. 



3. Conglomerate 20 feet. 



4. Red and blue clay 30 feet. 



Total 80 feet. 



In the red and blue clay (No. 4) of the above section I found the fossil re- 

 mains of a part of a large saurian (Belodon?), and in the same clay found the 

 cast of a unio which I have called Unio dockumensis. 



The sandstones and conglomerate are very persistent in character through- 

 out this entire district. In places there is a large amount of mica in the sand- 

 stones in scales one-sixteenth of an inch square. 



The following section was made at the falls of White River, in Blanco 

 Canyon, about twelve miles below Mount Blanco. Beginning at the bottom : 



* United States Geological Report, Vol. Ill, 1880. 



