148 GEOLOGY OF THE HIGH PLATEAUS. 



impregnating the sandstones and shales in sufficient quantity to attract both 

 miners and capital to the locality. 



The Shindrump has but a few exposures within the District of the 

 High Plateaus. The best example is seen at the Red Gate, at the foot of 

 Rabbit Valley, where the Fremont River passes out into the desert waste in 

 the heart of the Plateau Province. A belt of this formation is seen near 

 the summit of the Water-Pocket flexure, flanking the northeastern part of 

 the Aquarius a few miles from its base. It is brought up to daylight south- 

 west of the Markdgunt by the Hurricane fault, and the beds are there 

 sharply flexed in the vicinity of the fault-plane, but quickly smooth out to 

 the eastward and southward. The principal area of the Shindr ump is south 

 of the Vermilion Cliffs, in the northern part of the Kaibab District, around 

 the junction of the Grand and Green and in the San Rafael Swell. Gen- 

 erally speaking, it is usually found as the first terrace above the Carbonif- 

 erous in the areas of maximum erosion. 



THE TRIAS. 



Next above the Shindrump shales is found an extensive series of sand- 

 stones constituting the Trias. Probably no formation in Southern Utah is 

 better exposed, but notwithstanding this, it has not in this part of the Pla- 

 teau Province hitherto yielded a solitary fossil of any kind. Still we are 

 not in doubt about the correlative age of the group for its continuity with 

 beds found by Newberry in New Mexico, and yielding a distinctly Triassic 

 flora; its further continuity and identity with Red-beds in the Uintas having 

 a Jurassic fauna above and the unmistakable Shintirump shales below; and, 

 lastly, its identity with the beds of Idaho, which furnished Dr. Peale a well- 

 marked Triassic fauna, are sufficiently certain. 



The contact with the shales below is usually conformable, but in the 

 vicinity of the Hurricane fault, where the whole Triassic series is displayed, 

 the junction is often unconformable. The separation, however, of the 

 Trias into an upper and lower series, so far as Southern Utah is concerned, 

 is based upon lithological grounds chiefly. It is also a matter of great 

 convenience to efi"ect this separation, since each division has its own topog- 

 raphy, and their distributions differ notably. There is, also, a decided con- 



