6T.J0HN.] VICINITY OF TOGWOTEE PASS. 471 



THE CONTINENTAI. WATERSHED, VICmiTY OF TOGWOTEE PASS. 



'■) 



The Black Eock Creek, near the foot of Station XLIX, opens into a 

 fine, high, shallow basin, which extends thence in an easterly dii-ection 

 several miles to the summit of Togwotu Pass, where the altitude is, 

 according to Captain Jones, 0,621 feet. The ascent of the valley is over 

 successive benches having something the character of morai^ial 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 

 deiived from the disintegTation of the Triassic " red beds," and wherever 

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

 uriant herbaceous gTowth. 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 hght-drab indurated calcareous 

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

 show a limited bhiff exposure of light-drab clays and light fragment- 

 ary limestone, dipping gently southwestward. Although no fossils were 

 observed in these dei)osits, 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 volcauic-capped crest south of Togwotee 

 Pass, show hght-brown earthy deposits, gently inclined south or south- 

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

 ridge of the ]\Iount Leidy highlands. Higher up the valley brown shaly 

 sandstone layers are apparently associated Avith these dLcposits. 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 up 

 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 Pork 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 trachji;ic 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 exposiu'es of 50 feet 

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

 the valley Avhere they were first encountered. 



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

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

 tiu-esque surroundings. It is filled Avith 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 charmiug 

 little intervales, and miniature teiTaces bright with many-hued fiowers. 

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

 sweep up into the mountain heights on either hand, whose lofty, pi'ecipi- 

 tous waUs form a majestic gatewaj' 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-^ 



