SILVER MINENG IN COLOEADO. 603 



been already said, as the veins of the district are generally of one type, differ- 

 ing chiefly in the richness and quantity of their silver-bearing ores. Among 

 the more important are the Griffith and Summit, on the east side of the stream, 

 and the CHflT, Astor, Beecher, New Boston, and others, on the v^'-est side. The 

 first-named strikes north 75° east, dips vertically, and is developed to a depth 

 of about 130 feet. A claim, 300 feet in length, is being worked by the Wil- 

 son and Cass Company. About 700 tons of ore had been taken out at the 

 date of the writer's visit, some of which was of excellent quality, the greater 

 part, however, requiring concentration. For this purpose the company had 

 erected dressing works, which wiU be noticed further on. The Summit, Cliff, 

 and Astor have produced small lots of very rich ore. The New Boston is a 

 large and well-defined lode, carrying a wide seam of galena, which, so far, is 

 not very rich in silver. 



Tunnels. — During the past year some important enterprises have been in 

 progress in the Georgetown district, having for their object the exploration of 

 the country by means of tunnels. The natural features of the region are most 

 favorable to such a method, as the hill-sides are not only very abrupt, but the 

 lodes are generally parallel to each other, and coincide nearly with the trend 

 of the hill, so that a tunnel, driven in from the valley at a right-angle to the 

 general direction of the veins, is likely to intersect several of them in the 

 course of its progress. The tunnel affords, at the same time, the most advan- 

 tageous method of exploitation, as the vein is worked from below upwards, 

 and the necessity of raising rock and water is obviated. On the right-hand, 

 or west fork of the stream there are three tunnels, including the Terrible, al- 

 ready noticed, which are being driven northerly into Sherman and Brown 

 Mountains. On the left-hand fork is the Marshall tunnel, piercing Leaven- 

 worth Mountain, in the neighborhood of the Equator mine, while, in the 

 autumn of 18G9, several others were proposed, among them one^ to enter 

 Leavenworth Mountain from the north side, opposite to the Marshall tunnel, 

 and another to penetrate Columbia Mountain,^ which lies on the northwest 

 side of the main branch of South Clear Creek, about two miles below 

 Georgetown. 



1 This is now in progress, and is known as the Helmick timnel. 



2 Also said to be iu progress, and known as the Morris tunnel. 



