418 E^POKT UNITED STATES GEOLOGICAL SURVEY. 



accompanying plate, Section D. This profile exhibits approximately the 

 relative position and present distribution of the sedimentaries in this part 

 of the range. 



South of the West Teton Yalley, a huge tilted block of the sedimenta- 

 ries, four to fiA'C miles in breadth, constitutes the west flank of the moun- 

 tain between that stream and Goodfellow's Creek, on the southeast angle 

 of which Station XXXVII was established. The eastern face of this 

 ridge is wrought into amphitheatres and colossal i)ier-heads, ou the one 

 hand extending out into the granite-floored Alpine Basin in which West 

 Teton Creek rises, and on the other the smaller basin at the head of 

 Goodfellow's Creek, which is also based on the light-colored granite, from 

 which rise ridges capi)ed by remnants of the more ancient sedimentaries. 

 The latter basin is bounded on the south by a line of steep acclivities 

 with precipitous coping of Siluriaii limestone, which culminates in a lofty 

 isolated mountain, having the semblance of a huge architectural pile, 

 nearly 11,000 feet in actual altitude, to the southeast and east of which 

 the axial crest of the range swings round in broad-topped summits bear- 

 in g characteristic remnants of the quartzite and Quebec. The section here 

 disi)layed is very like that previously described, as a comparison of Sec- 

 tions t> and E will render apparent. The latter section is also carried 

 across the range along a nearly east- west line. 



The volcanics reach an elevation of between 500 and 800 feet along 

 the west foot of the mountain, and at about 1,000 feet are succeeded by 

 ledges of buff-red hard sandstone. The latter continues to hold its place 

 in the wooded ascent, whose inclination apparently closely corresponds 

 to, as it is determined by, the dip of the sandstone pavement to a point 

 about four and a half miles from the edge of Pierre's Basin, where they 

 terminate in a range of steep bluffs whicli define the west side of lateral 

 gulches draining into the West Teton. In the higher x>arts of this bench 

 a section of 300 to 500 feet vertical thickness is more or less well exposed, 

 the upi)er portion of which shows a handsome, even-bedded, reddish- 

 buff, laminated sandstone, which forms a heavy bed, including a thick 

 stratum of intensely hard, rough, rusty-gray rock resembling burr-stone, 

 which in places forms the coping. Tliis bed is underlaid by an equal or 

 greater thickness of red and chocolate-brown indurated arenaceous shales, 

 interbedded with Mglit-drab, sometimes nodular, shaly, non-fossiliferous 

 limestone and deep-red laminated sandstone, making up the lower third 

 of the bluff exposure. The above deposits rest conformably upon bluish- 

 gray and drab limestone, containing a small Zaphrentoid coral and an 

 obscure Spirifer, and which forms the top of the Carboniferous limestone 

 series ; dip, 10° to 15°, northwestward. 



The saddle connecting the above bluff with the ridge of Station 

 XXXVII, a mile to the east, is pa,ved with the limestones, of which 

 ;about 500 feet are exposed in the abrupt declivity in which the eastern 

 face of this ridge breaks down. In the summit at Station XXXVII the 

 uxDper layers of dark-drab limestone dip at angles of lo^ to 20° westward, 

 and is underlaid by gray and buff cherty limestone with calcite, and 

 containing a Lithostrotion {L. Whitnei/i f) and aform of Syrincjopora. This 

 ridge is blocked out of the Carboniferous limestones, and the narrow 

 gulch which separates it from the next west-ljing sandstone ridge is 

 floored with large exposed surfaces of the rock, which arc here and there 

 obstructed with sinlii-holes, and on the lower side pretty little lakelets 

 are hollowed out of the soft red deposit at the foot of the bluff". When 

 the rapidly-descending gulches reach the horizon of the heavy-bedded 

 Niagara, their beds are precipitated several hundred feet down steep 

 slopes, w^hich, earlier in the season, when the streams are full from the 



