106 



GEOLOGICAL SURVEY OF THE TERRITORIES. 



with carbonate of copper in limestones. This corresponds to the loca- 

 tion of the most productive silver mines in Utah. They are almost 

 situated in limestones at the heads of the caiions, and the ores are ores 

 of lead contaiuint;' silver. The minerals I obtained iit Ogden are the 

 followin.i;' : micaceous hematite, iron pyrites, galenite, magnetite, 

 graphite, azurite, malachite, garnets, quartz, chlorite, talc, serpentine, 

 jasper, hornblende, serpentine, aud calcite. 



On the 19th of June Mr. Jackson started on a i>hotographic trip to 

 Little Cottonwood Oaiion, on which trip 1 accompanied. From Ogdea 

 to Salt Lake City we took the Utah Central Kailroad, which skirts the 

 edge of the mountains. The granitic rocks extend for soiue distance 

 below Weber Cailon, but as we near Salt Lake City the limestones form 

 the base of the mountains, near which are a number of limekilns. The 

 limestone for the kiius seemed to be taken from the upper layers, prob- 

 ably because the lower ones are siliceous, as at Ogden. 



The caiions which cut through the Wahsatch Range near Salt Lake 

 City are as follows, in their order from north to south: Red Butte, Emi- 

 gration, Parley's, Mill Creek, Big Cottonwood, and Little Cottonwood. 

 At the liead of the latter are some of the best silver mines to be found 

 in Utah, and among them is the famous Emma mine. Leaving Salt 

 Lake Cit^^ we take the State road, aud after a ride of ten miles in a 

 southeasterly direction, passing between thriving farms dotted with 

 comfortable-looking houses, we turn to the left and strike across the 

 country to the mountains. Directly before us is the highest point in 

 the Wahsatch Range, the Twin Peaks, over 12,000 feet al)ove sea-level. 

 As we ride along we see distinctly marked on the sides of the mount- 

 ains in front of us the water-lines of the former shore of the Great 

 Salt Lake. These old shore-lines are distinctly marked on the mount- 

 ains, on all sides of the lake, and on the islands in the lake. We pass 

 over numerous terraces and at length reach the mouth of the canon. 

 Here there are no less than seven distinct terraces, some of them, how- 

 ever, due to the action of the Cottonwood Creek. Near the mouth of the 

 caiion there are smelting- works, to which ore is brought from the mines 



at the head of the creek. Inside the 

 canon we find ourselves between high 

 granite-walls, rising precipitously on 

 either side of the creek. The first 

 thing to attract our attention is the 

 conspicuous bedding of these gran- 

 ites. The dip is east at an angle of 

 50O to 70°. The granite is of a "light- 

 gray color, composed of white feld- 

 spar, (orthoclase,) quartz, and black 

 mica. The bottom of the canon is 

 strewn with bowlders of granite, 

 "which lie scattered over it in inextri- 

 cable confusion. In miiny of them 

 (Fig. 25) I noticed veins of feldspar 

 of about two ini;hes in wult-h crossing 

 each other at right angles. Auotber 

 BLOCK OF GRANITE WITH FELDSPATHic SEAMS, uotlccable fcaturc lu theso granites 

 is the occurrence of rounded i)ebble-like masses, of a dark color, inclosed 

 in the gray matrix. Professor Silliujan, (Silliman's Journal, vol. iiijpiige 

 19G,) referring to these, says "These granites are probably metamorphic, 

 of coglomerates, an opinion first suggested to me by Professor W. P. 

 Blake." As he also further states, there is a pebble like roundness in 



Fig. 25. 



