SILVER MINING IN COLORADO. 



591 



west side of the stream, Democrat, Columbia or Colfox, and Douglass Moun- 

 tains, the latter being at the confluence of the south branch with South Clear 

 Creek. On the opposite or eastern side of the valley, a half-mile below the 

 town, is Griffith and Summit Mountains. In all these hills, and in others 

 adjacent, whose names have not been mentioned, the work of exploration has 

 been carried on, and, in some cases, attended with very important results. 



The Veins. — The veins of the Greorgetown district are highly argen- 

 tiferous, but they contain little or no gold. Some of them are reported to 

 be slightly gold-bearing, but so far as the writer's observation extends, the 

 typical veins of the region have no gold whatever. The country-rock is 

 generally granite and gneiss, presenting many lithological and mineralogical 

 varieties. The prevailing character is, perhaps, gneissic, but many varieties of 

 structure and mineral composition occur in close proximity to each other, and 

 sudden and frequent transitions from one form to another may be observed 

 throughout the district. 



The veins, generally, are not very wide. Like the gold-bearing lodes of 

 Gilpin County, they present among themselves a striking similarity in course 

 and dip; and, further, the prevailing direction is very nearly the same as that 

 of the veins about Central City. With rare exceptions, the course of veins, 

 observed by the writer in this district, is between due east and west, on one 

 hand, and north 55° east on the other. The last named course, itself some- 

 what exceptional, is that of the Equator, one of the most prominent lodes of 

 the district. The Terrible, another of the most distinguished veins, strikes 

 north 77° east, while the majority of veins, less developed than those first 

 named, have a course of due east and west. In this statement the true course 

 is spoken of, allowing about 15° easterly variation in the magnetic course. 

 The veins dip generally at a high angle, in many cases vertically. Like those 

 of Gilpin County, they are regular, well-defined fissures, and are not faulted. 

 Their other natural features, the character of the gangue and ore, and the 

 mode of occurrence and value of the silver-bearing and other associated min- 

 erals, will be more fully shown in the following description of some of the 

 best developed and most important examples. 



Terrible. — The Terrible mine is located on Brown Mountain. This 

 mountain is one of those on the north side of the right-hand fork of the 



