bt.jghk.] SECTION ACROSS CAEIBOU EANGE. 395 



52. Chocolate-colored sliales with indurated arenaceous layers, ob- 

 scurely exposed. 



53. Chocolate-brown and gray shaly sandstone. 



54. Chocolate-drab shales and sandstone. 



55. Gray sandstone. 



56. Unexposed space. 



57. Brownish-gray, laminated, thin-bedded sandstone, 25 feet exposed. 

 Dip steeply northeastward. 



58. Bed shales. 



59. Sandstone ledges, interbedded with chocolate-red shales, forming 

 a heavy deposit ; dip northeastward at an angle of 45°. 



60. Dark drab shales, with two or more ledges of rusty reddish-gray 

 sandstone, a heavy deposit several hundred yards across. 



61. Brownish sandstone. 



62. Bed shales. 



63. Beddish sandstone. 



64. Bed shales. 



65. Drab limestone and light-drab indurated calcareous shales, exposed 

 many hundred yards, nearly horizontal or gently undulating, overlaid 

 by beds 64-61, conformably. 



66. Pale-red shales. 



67. Wide space in which the continuity of the strata is interrupted. 

 But the limestone ISTo. 65 and superimposed. beds gently descend in pass- 

 ing up the valley, and it seems probable that they form a sag or syn- 

 clinal east of the abrupt displacement which shows deposits that agree 

 quite closely with the lithology of the sandstone appearing in the upper 

 part of the broad, flattened uplift with which then identity is inferred 

 with a degree of probability. 



68. Beddish sandstones and shales, obscurely seen in the axis of the 

 displaced beds, and may be the equivalents of Nos. 61 and 62. 



69. Dark-drab shales. 



70. Beddish-brown weathered sandstone; a heavy ledge, which on the 

 east is suddenly uplifted into a position past the vertical, the western 

 exposure protruding in the steep valley-side, dike-like, and inclined 

 southwestward at angles of 75° to 80°. These two masses are seen to 

 be connected by an undulating arch of sandstone, gently inclined to 

 the westward, the angles of sudden flexure exhibiting unmistakable 

 evidence of the intensity of the strain to which the beds were subjected, 

 in the broken and confused condition of the layers at those points. 

 There are apparently two distinct horizons of the brown-gray sandstone 

 and drab shales included in the uplift, which probably are identical 

 with the upper horizons, Nos. 61, 60, seen in the broad level space to the 

 east. 



The valley here opens out into the mountain basin, the stream branch- 

 ing, the main fork continuing west and Iowa Gulch coming from the 

 south ; in the intervening upland ridges and along the crest of one of the 

 northeast spurs descending from Mount Caribou the following numbers 

 (71-101) appear: 



71. Hard, thin-bedded sandstones, and brown-drab shales, several 

 hundred feet, dip steeply southwestward. 



72. Chocolate-colored and red shales, heavy deposit. 



73. Gray thin-bedded sandstones and shales. 



74. Bed shales. 



75. Shaly gray sandstone; dip 60°, southwestward. 



76. Variegated chocolate-colored, drab-blue, red, and drab shales. 



