KSQiacn.] WIND RIVER RANGE MET AMORPHIC ROCKS. 69 



at the extreme southern end of the Wind Biver Range, where the transi- 

 tion into the Sweetwater Hills begins, we will find : That the granite of 

 the subsidiary range has disappeared from the surface; that steeply- 

 dipping schists occupy the region where we might expect to find the 

 former : that the granite of the main chain, the schistoid rocks of its 

 eastern slope, and the granites of the higher foot-hills have sunken out of 

 sight ; that the granites of the lower foot-hills occupy points of higher 

 elevation than they do farther to the northwest, and that the relations 

 of the quartzite and unchanged sedimentary beds to the latter are not 

 affected. We observe, furthermore, that the character of the schists 

 here exhibited is not identical with that observed in the main chain, and 

 that their thickness is by far greater. From the relative positions of these 

 various groups it follows that the schists in question cover the granite of 

 the subsidiary range. That of the main chain and of the higher por- 

 tions of the foot-hills has probably pinched out in part and lies buried 

 beneath the younger masses elsewhere found near the base of the hills. 

 In the hills near Miner's Delight this granite shows a dip of about 25° 

 to the eastward and remains conformable with the sedimentary beds 

 superincumbent. 



Within the area upon which the schists are exposed, we observe a 

 number of varieties. Micaceous and hornblendic are the two chief 

 varieties, but gneiss and chlorific schists are not wanting. They dip 

 steeply, ahnost 90°, to the eastward. From the hills south of Camp 

 Stambaugh their strike, and in a measure their dip, can be beautifully 

 observed. Seen from the summit of some point, the harder strata, 

 which have resisted erosion, give the ground a regularly furrowed ap- 

 pearance. This extends frequently for some distance, and may be sud- 

 denly broken off. So far as could be observed, the dip of the schists 

 decreased as we proceeded toward its junction with the younger gran- 

 ites. A number of good exposures in small canons furnish ample 

 information toward the southern end of the metamorphic area. 



Reviewing in a few words the result shown by all these occurrences, we 

 have, following a line from below South Pass to Miner's Delight, a sinking 

 of the oldest granites accompanied by the appearance of younger schists, 

 an elimination of the rocks elsewhere composing the central portion of 

 the Wind River Range, and arise of the youngest granites of the region. 

 It seeems that the enormous bulk of material from which the rocks com- 

 posing the highest mass of the range was obtained was exhausted near 

 this line. The original iiroducts of deposition there accumulated had 

 come to an end, and only those now represented by the younger granites 

 existed at the locality. This condition of affairs permitted the older, or 

 probably even oldest, sedimentary products to rise sufficiently high to 

 reach to the present surface. Their quantity was not sufficiently great 

 to rise to the same elevation that the masses farther northwest reached, 

 or we should to-day be without South Pass. From subsequent state- 

 ments it will be seen that farther eastward we have an analogous case 

 where still another member of this same group disappears. 



An important feature of this older metamorphic area is the existence 

 of metalliferous veins. The mines of South Pass, Atlantic City, and 

 Miner's Delight are located hi the old dark-colored schists; all of them 

 contain gold. This distribution explains why as yet no remunerative 

 veins have been found in the metamorphics of the main chains. A number 

 of metalliferous veins have there been observed, but none of them carry 

 the precious metals in quantities greater than mere traces. A number 

 of lodes have been discovered, and some exaggerated reports thereabout 

 are current. So far as our observations extend, the metal contained in 



