SILVER 'AXD GOLD. 211 



2.09.12. The Gunnison region lies on the western slope of the 

 Continental Divide and embraces both mountains and plateaus. 

 West of the main and older range are the later Elk Mountains, in 

 which several mining districts are located. Aspen has already 

 been mentioned, and the long series of ore bodies in the Carbonif- 

 erous limestones. The other principal districts are Independence, 

 Ruby, Gothic, Pitkin, and Tin Cup. The ores at Independence 

 are sulphides with silver, in the Archaean granite rocks. In the Tin 

 Cup district the Gold Cup mine is in a black limestone and con- 

 tains argentiferous cerussite and copper oxide. In the Ruby dis- 

 trict the ores are in the Cretaceous rocks, and in the Forest Queen 

 they are ruby silver and arsenopyrite, partly replacing a porphyry 

 dike. On Copper Creek, near Gothic, a series of nearly vertical 

 fissures traverse eruptive diorite. They contain sulphide of silver 

 and native silver. The Sylvanite is one of the principal mines. 1 



2.09.13. Eagle County. The lead-silver mines of Red Cliff 

 have already been mentioned (Example 30c), and also the under- 

 lying gold deposits. The Homestake mine, northwest of Lead- 

 ville, over toward Red Cliff, is on a vein of galena in granite, and 

 was one of the first openings made in the region. 2 



2.09.14. Summit County. The Ten Mile district, which is the 

 principal one, has been mentioned under Example 30. The Pride 

 of the West Tnine, on Jacque Mountain, is peculiar, being on a 

 quartz porphyry dike which is partly replaced by ferruginous quartz 

 and barite. Lake County, containing Leadville, has been treated 

 under Example 30. Mention should also be made of the placer 

 deposits in California Gulch, which first attracted prospectors to 

 the region in 1860. In its eastern part Summit County borders on 

 Clear Creek County, and at Argentine are some veins related to 

 those of the latter. They are high up on Mount McClellan, and 

 are remarkable for the veins of ice that are found in them. 3 



1 F. Amelung, *' Sheep Mountain Mices, Gunnison C unty," Engineer- 

 ing and Mining Journal, Aug. 28, 1886, p. 149. F. M. C iadwick, "The 

 Tin Cup Mines, Gunnison Count}', Colorado,'' Engineering and Mining 

 Journal, Jan. 1, 1881, p. 4. See also Example I2d for iron mine-. 



2 Guiterman, " On the Gold Deposits of Red Cliff," Proc. Colo. Sci. Soc., 

 1890. " On the Battle Mountain Quartzite Mines," Mining Industry, Den- 

 ver, Jan. 10, 1890, p. 28. E. E. Olcott, "Battle Mountain Mining District, 

 Eagle County," Engineering and Mining Journal, June 11 and 18, 1887, 

 pp. 417, 436 ; May 21, 1892. G. C. Tilden, " Mining Notes from Eagle 

 County," Ann. Rep. Colo. State School of Mines, 1886, p. 129. 



3 E. L. Berthoud, "Oa Rifts of Ice in t\w Rocks near the Summit of 

 Mount McClellan," etc., Amer. Jour. Sci., iii., II. 108. 



