GEOLOGICAL SURVEY OF THE TERRITORIES. 61 



order of sequence, from the triassic to the cretaceous inclusive. In study- 

 ing the section from the north side, commencing with the open area, 

 which we supposed to be occupied with upper cretaceous clays, the first 

 ridge is a yellowish-gray sandstone, inclining 35° west-northwest. 



2. A series of steel-gray slaty shales, (No. 2 cretaceous section.) The 

 usual scales and other remains of fishes are abundant, fixing this bed 

 as positively lower cretaceous — one hundred and fifty feet in thickness. 



3. The yellow-gray and gray sandstones of the lower cretaceous, (jSTo. 

 1,) inclining 35°, two hundred feet. 



4. A series of layers of remarkably variegated clays, with one of the 

 layers of rusty sandstone. 



5. A bed of fine gray sandstone, weathering brown, four feet, passing 

 into clay, with a slight reddish tinge, inclining 30°. In these beds are 

 some thin layers of siliceous limestone, mostly made up of a species of 

 ribbed Terebratula, undoubtedly Jurassic, eighty feet. 



6. Then comes about one hundred and fifty feet of alternate layers of 

 fine gray sandstone and yellow gray arenaceous clay, dipping 50°. 

 Jurassic fossils abundant. 



7. A singular-looking series of variegating clays, about fifty feet 

 thick, varying from a chalky white gray, ashen gray, light red, deep 

 red, purple, in alternate bands ; the colors giving a picturesque effect 

 to the eye. They weather into curious rounded ridges, inclining 65°. 



8. A thick bed, two hundred feet ; grayish sandstone, weathering 

 brown, inclining 40°. 



9. A grassy interval, composed of soft beds, somewhat variegated, 

 with thin layers of limestone, with Terebratula, Ostrea, and other Jurassic 

 fossils. There is a considerable increase of lime in these beds. Just 

 over these marls is a thick bed of somewhat laminated limestone, with 

 fossils — fifty feet thick — dipping 26°. Above the limestone is another 

 series of sandstones, marls, and clays, fifty feet thick, with thin layers 

 of limestone, made up of Jurassic fossils. Then comes a series of sand- 

 stones, massive ; a portion of them weathering with a reddish hue, 

 forming a ridge, which rises one thousand feet above the channel of 

 Henry's Fork, inclining 26°. Above this sandstone is a thin series, 

 fifty feet, of alternate layers of sandstone, limestone, and argillaceous 

 marls, with Terebratula, Ostrea, and other Jurassic fossils. This I regard 

 as the upper line of the Jurassic beds. 



10. The gray sandstone, weathering yellow, which form the upper 

 portion of the triassic ridges, is very thick and massive. It is exposed 

 here so as to be studied to the best advantage. I have never seen 

 finer illustrations of oblique layers of deposition. The sandstone shows 

 a vertical slice through it, one hundred feet or more, where all the irregu- 

 larities are as perfect as possible. On the opposite side of the gorge 

 the sandstone has an interesting cave in the side, at least fifty feet in 

 every direction, and showing equally as clear the conditions of the depo- 

 sition of the sediments. The cave is full of holes and crevices, which give 

 shelter to multitudes of bats and other animals. Masses of their excre- 

 ment project from the crevices, and sometimes run down the walls of the 

 cave. In many instances this black excrement of bats has been mistaken 

 for indications of petroleum. This cave has also been a favorite resort 

 for Indians, as is shown by the fires, the walls of stone laid up for de- 

 fense, the chipped flints and arrow-heads scattered about, and the rude 

 images marked upon the walls. The sides of the ridge are very rugged 

 and picturesque, weathered into a variety of architectural forms. The 

 texture of the sandstone is quite soft, yielding readily to the atmos- 

 phere, and the valley is filled with loose sand. This ridge forms the di- 



