GEOLOGICAL SUKVEY OF THE TEERITOEIES. 197 



and to get some idea as to the uniformity of character of its formations, 

 I accompanied Messrs. Jackson (our photographer) and Peale (mineral- 

 ogist) to Salt Lake City and Little Cottonwood CaSon, the latter being 

 about fifty miles south of Ogden. At that time, June 20, immense 

 snow-drifts still remained in all the upper parts of the canon, and made 

 it impossible to obtain more than a very general idea of the section. 

 The outer (western) part of the caSon is walled solely by the almost 

 white granite, which is extensively quarried, near its mouth, for the 

 Mormon temple, as well as for other uses about Salt Lake City. This 

 is entirely difierent from anything seen near Ogden. From the strike 

 of the bedding, it is evident that the line of outcrop would pass con- 

 siderably to the eastward of the crest of the mountain, in making only 

 a few miles of northing. The dip is westward, as is the case with most 

 of the metamor^jhic rocks near Ogden. Several of the large faces of 

 granite exposed in the quarry showed angular and rounded j)atches of 

 darker material, which were evidently sections of what had been more 

 or less rounded pebbles in the conglomerated mass, before its metamor- 

 l^hism. Unconformably upon this granite lies a heavy mass of ferrigu- 

 nous quartzites, whose northern continuation forms the Twin Peaks, 

 said to be the highest points of the range. Upon this, apparently con- 

 formably, lies a series of limestones, the lower jDart rather thin bedded, 

 the upper part in heavier layers. The lowest beds could not conven- 

 iently l3e visited. A short distance south of the Flagstaff mine, a small 

 mass of rock was found to be full of small fossils, including some char- 

 acteristic forms of the Sub carboniferous. A few others were found 

 scattered about in such condition as to satisfy me that the whole clus- 

 ter of mines surrounding the Emma and the Flagstaff is in Carbonif- 

 erous and Sub carboniferous rocks, so far as yet developed. While the 

 age of the lower part of the series was not determined, yet it was evi- 

 dent that there is nothing in the character of these beds which should 

 cause us to anticipate any considerable decrease in the metallic deposits 

 before reaching the underlying quartzites. At that level, however, 

 they are likely to be greatly diminished, if not entirely wanting.* 



Even on the comparatively moderate sloi^es of the head of the valley, 

 climbing is very wearisome ; and the lower part of the canon is hemmed 

 in by immense nearly vertical walls of granite, standing up out of steep- 

 . est slopes of debris. From these bare walls and steep slopes descend, in 

 winter, the avalanches which have buried so many teamsters and others, 

 and which will continue to thus destroy life and property until the 

 mining companies shall unite in constructing either a covered or an ele- 

 vated road for the transmission of ore and supplies as well as of pas- 

 sengers. The inexhaustible supply of granite, already broken by na- 

 ture to manageable size, would seem to make the construction of a 

 covered way extremely feasible. 



The limestones which form the base of the high-terrace shoulder of 

 the mountain, at the Warm Springs, just north of Salt Lake City, show 

 at one point a dip of 25<^ S. 38° E. They apparently belong to a sub- 

 ordinate fold of the western slope of the main anticlinal, similar to those 

 already described. 



On June 24 we started from Ogden on our northward journey, and 

 camped at the Hot Springs, about ten miles from that city. After 

 crossing Ogden Eiver, about two miles below the mouth of its canon, 



* As this report is passing through the press, I find that, in the Engine'eriug ami 

 Mining Journal of March 11, 1873, Mr. Henry Elngelmau states that a second quartzite 

 is in place in the Cottonwood section. The lower limestones must therefore be re- 

 ferred to the Silurian age, as at Ogden. 



