THOUSAND LAKE MOUNTAIN. 281 



the first conclusion seems to be that the movement took place after the 

 Laramie beds were deposited and before the Tertiary strata were laid down. 

 The contacts, however, between the Tertiary and Laramie beds have not 

 yet been studied and analyzed, nor have any good exposures of those con- 

 tacts in this vicinity been discovered. It is not impossible that through a 

 large portion of Cretaceous time this area was a part of an island under- 

 going a slow erosion, while just beyond the flexure to the eastward the 

 later Cretaceous members were accumulating upon an island coast ; that at 

 a later epoch the island was submerged, and received a deposit of Lower 

 Eocene beds. This supposition has considerable support in facts which 

 will be brought forward in the next chapter, and leads to the conclusion that 

 a long interval of disturbance and erosion separated the Cretaceous from 

 the Tertiary throughout this part of the Plateau Province. The absence 

 of more than 5,000 feet of strata between the Lower Eocene and the for- 

 mation upon which it reposes is a very striking fact, and the simplest expla- 

 nation is here the best. 



The Jurassic white sandstone is disclosed all around the mountain. It 

 has the same familiar fades which has been adverted to in the preceding 

 chapters upon the Markagunt and Paunsagunt Plateaus — a grayish-white 

 massive sandstone, wonderfully cross-bedded, and weathering into inacces- 

 sible domes of peculiarly solid and bold aspect. The upper Jurassic shales 

 appear to be absent, at least they were not detected, and the eroded con- 

 dition of the sandstone at the time of the deposition of the Tertiary is a 

 sufficient reason for presuming that if the shales once existed here, and I 

 doubt not that they did, they have been swept away. 



Beneath the Jurassic appear in normal order and relations the Ver- 

 milion Cliff sandstones (Upper Trias) and the Shinarurnp shales. These 

 formations have the same aspect as in the lower terraces which front the 

 Kaibabs in the Grand Canon District. The Vermilion Cliff series has the 

 same succession of sandstones and siliceous shales, usually bright red, but 

 sometimes patched with bright yellowish brown. They are best exposed 

 upon the southern flank of the mountain at the Red Gate. The Shinarurnp 

 has the same band of conglomerate, consisting of fragments of silicified 

 wood imbedded in white sand, which is seen in the vicinity of the Hurri- 



