st.johx.] VICINITY OF TOGWOTEE PASS. 471 



THE CONTINENTAL, WATERSHED, VICINITY OF TOGWOTEE PASS. 



The Black Bock Creek, near tlie foot of Station XLIX, opens into a 

 fine, nigh, shallow basin, which extends thence in an easterly direction 

 several miles to the siinmiit of Togwotu Bass, where the altitude is, 

 according to Captain Jones, 9,621 feet. The ascent of the valley is over 

 successive benches having something the character of morainal accumu- 

 lations, through the lower edges of which the stream breaks its way in 

 narrows, opening above into beautiful park expanses, diversified with 

 grassy slopes and forest-clad border hills. The southern hills are very 

 generally clothed with spruce ; the opposite slopes, exposed to the sun, 

 appear to be the congenial habitat of the pine. In the lower portion of 

 this valley we meet with red earth, supposed with good reason to be 

 derived from the disintegration of the Triassic "red beds," and wherever 

 these deposits occur in valley depressions they are associated with lux- 

 uriant herbaceous growth. Indeed the valley, like so many of the pass- 

 valleys in this region, is excavated out of these deposits. In the slopes 

 south of the stream obscure exposures of light-drab indurated calcareous 

 deposits occur, and at one point in the south bank of the creek, these 

 show a limited bluff exposure of bight-drab clays and light fragment- 

 ary limestone, dipping gently southwestward. Although no fossils were 

 observed in these deposits, they are believed to belong to the Jurassic. 

 Beyond the latter, to the south, such exposures as are visible in the 

 forest-clad outlying slopes of the volcanic-capped crest south of Togwotee 

 Bass, show fight -brown earthy deposits, gently inclined south or south- 

 westward, which appear to merge into the deposits constituting the axial 

 ridge of the Mount Leidy highlands. Higher up the valley brown shaly 

 sandstone layers are apparently associated with these deposits. The 

 banks of the stream also exhibit exposures of a steel-brown deposit like 

 that resulting from the decay of the volcanic breccia. As we pass np 

 the valley the breccia hillocks become higher and more rugged, and 

 associated with the igneous bowlders scattered over the surface, others 

 of hard sandstone, and other quartzose rocks occur, which were probably 

 brought down from the neighborhood of Buffalo Fork Mountain. There 

 are a variety of products referable to volcanic origin besides the gener- 

 ally prevalent breccia, and in the banks of the stream occur banded 

 dark-brown and drab soft sands, nearly horizontal or slightly inclined 

 southward. The trachytic breccia and huge masses of the sombre, green- 

 tinged conglomerate become more and more abundant, and in places are 

 noted heavy-bedded horizontal ledges of reddish-brown weathered por- 

 phyritic trachyte. The breccias appear in particularly rugged exposures 

 in the west slope of the summit, where they show exposures of 50 feet 

 in thickness, at an elevation of 700 to 900 feet above the lower end of 

 the valley where they were first encountered. 



The approaches to the summit of Togwotee Bass are easy, and the spot 

 itself is one of the most interesting, both for its geologic as also its pic- 

 turesque surroundings. It is filled with open grassy undulations whose 

 hollows hold pretty lakelets, the declivities dotted with beautiful groves 

 of pine and spruce, and threaded by tiny rivulets bordered by charming" 

 little intervales, and miniature terraces bright with many-hued flowers 

 and the white blossoms of a delicate clover. Densely wooded taluses. 

 sweep up into the mountain heights on either hand, whose lofty, precipi- 

 tous walls form a majestic gateway to the pass across the great water- 

 shed. 



The mountain on the southwest side of the pass afforded a good oppor- 

 tunity to gain a general knowledge of the character of the vast sedi- 



