176 ECONOMIC GEOLOGY OF SILVERTON QUADRANGLE, [bull. 382. 
been successfully worked. An extensive tunnel has been run in from 
the Animas River near the mouth of Burns Gulch, and a costly mill 
has been erected to treat the ore when it should be found. The prop- 
erty became involved in legal difficulties, and in 1899 all work had 
ceased before ore had been discovered in paying quantities. 
LODES OF SUNNYSIDE BASIN. 
General. — Although the Sunnyside mine is the only one in the 
basin now producing, there are several other large lodes which have 
in the past produced ore from superficial workings. In the general 
character of their ores they show much similarity. They are all of 
prevailingly low grade, although the Sunnyside contains masses^ of 
richer ore carrying free gold. The lodes are unusually massive, in 
some cases over 50 feet wide, and all carry abundant rhodonite. The 
ore minerals are galena, sphalerite, chalcopyrite, pyrite, and some- 
times tetrahedrite and free gold. The ore minerals are usually rather 
evenly scattered through a quartz gangue, and the ores are more sili- 
ceous and the galena is more finety crystalline than in those of the 
Silver Lake Basin. The large veins at the head of Lake Emma are 
curved and show abrupt changes in their courses. The cause of these 
irregularities is not apparent. 
Sunny side mine. — Situated in the basin at the head of Eureka Gulch, 
this mine enjoys the distinction of having been an almost continuous 
producer from the first discover}^ of the region. It is to-day one of 
the few mines in the quadrangle that are actively working on a con- 
siderable scale. The deposit, like many another prominent lode in 
the district, was located in 1873, Avhile the land was still held by the 
Indians, and afterwards relocated when the San Juan country was 
thrown open to settlement in 1874. It was worked as a prospect in 
£;; 1875, and about four years later produced considerable ore. Thomp- 
son Brothers worked the mine for several years, during one of which 
they are said to have taken out $385,000. The rich gold ore which 
made the early exploitation profitable finally gave out, A 10-stamp 
mill was erected at the outlet of the lake and an attempt was made 
to concentrate the lower-grade ore. The effort resulted m failure. 
Finally, about 1890, J.. H. Terry put up the present mill in Eureka 
Gulch and operated it successfully. About 1896 this mill was con- 
nected with the mine by a wire-rope tramway. In 1899 a second mill 
was completed at Eureka, designed to relieve the work of the upper 
mill by concentrating the lower grades of ore which do not require 
amalgamation. A tramway was also constructed connecting the two 
mills. 
The Sunnyside lode is very large — 30 to 50 feet in width. Its gen- 
eral strike is about N. 50° E. and it dips to the southeast at 65° or 70°. 
Toward the northeast it passes through a saddle, where it is known 
as the Sunnyside Extension lode, and continues down Placer Gulch. 
M«,| 
