420 EEPOET UNITED STATES GEOLOGICAL SURVEY. 



erosive phenomena liere encountered, tlie fashioning of the Alpine basins 

 and the cutting of the canons through which their gathered waters flow 

 to the plain, may well be questioned. 



To the south still, a similar but much norrower tilted table lies be- 

 tween the cauons of Goodfellow's and Fox Creeks, the geological features 

 of which are a repetition of what has already been described. On the 

 southeasternmost angle of this great upraised block of sedimentary rocks 

 Station XXXVIII was established, four miles south-southwest of the 

 preceding topographic station. This point commands, on the northeast, 

 a circumscribed basin at the head of a branch of Goodfellow's Creek, 

 which is quite surrounded by the sedimentaries, which form a broken 

 rim of variable height, sustained by accumulations of debris which slope 

 steeply to the bared and glaciated Avhite granitic floor. The western 

 rim sweeps up into the abrupt acclivities capped by several hundred 

 feet thickness of the Carboniferous limestones; to the right and left 

 great arms are extended eastward and united in a lofty summit nearly 

 11,000 feet in height, which inclose the basin within a wall of Lower 

 Silurian deposits. 



Fox Creek ojiens out into a similar basin to the southeast of Station 

 XXXVIII, which, however, is mainly floored by the quartzite, with 

 remnants of the Quebec limestones standing as isolated buttes and 

 tables which reach quite across to the eastern summit verge of the 

 range, the main channel of the stream only apparently hemmed in by 

 steep Archaean acclivities. 



The immediate crest of Station XXXVIII ridge is formed of the 

 Carboniferous limestones, which afford the usual organic evidence of 

 their age. These are immediately overlaid by a series of deep red 

 arenaceous shales and sandstones, holding interpolated beds of nodular 

 and fragmentary drab and chocolate-stained limestone, capped by a 

 heavy deposit of buft' and pale red even-bedded sandstone and tlie 

 burr-stone ledge, which constitute the roof of the great foreland de- 

 scending into Pierre's Basin. The relative position of the strata here 

 mentioned is show^n in section E, which is carried across the range 

 through Station XXXVIII along an east- west line. 



To the south and southeast of Station XXXVIII the summit of the 

 range presents a marked change in its geologic and concomitant to]io- 

 graphic features. It exhibits a wilderness of huge sedimentary ridges, 

 piled one above another, advancing towards ihe east, where they are sud- 

 denly broken down in long lines of steep and, in places, precipitous slopes, 

 with here and there a headland, like gigantic breakers transformed into 

 stone. The range is thence enveloped in these rocky sui-ges, which flnally 

 lap completely over the crest and eastern flank in the vicinity of the 

 southern extremity of the range, liiding from view the nucleus of Archfean 

 rocks. From the remnants or isolated exposures of the Palaeozoic series 

 in Jackson's Basin, on the east side of the range, we infer, with some 

 degree of confidence, the colossal proportions of the rocky billows that 

 once spanned the southern half of the great uplift out of which the Teton 

 Eange was carved, and in comparison with which those folds which re- 

 main %isible to this day are mere undulations. It is greatly to be re- 

 gretted that opportunity was lacking to penetrate to the summit of the 

 range in the portion intervening between Station XXXVIII and the 

 high point at the extreme south end, which was selected for the final 

 topographic Station, XLIII. Consequently, we are left somewhat in 

 doubt regarding the special expression, so to speak, of the disturbances 

 which here transpired, and the records of which are to be sought in 

 something more than hastily -executed examinations. Therefore, in giv-. 



