EM)Licn.] GEOLOGY PELICAN AND OTHER LODES. 297 



center a body of galena-ore of about 18 inclies, intermixed with blende, 

 pyrite, and tlie silver-ores pro])er. The gaugue-rock is composed of 

 quartz and feldspar j)artly decomposed. 



Another section of a central portion of the vein was obtained, (Plate 

 YI,) given in varying succession layers of the minerals composing the 

 ore, and thus showed a combed texture. The single layers were from 

 one-half to one inch in thickness, and not all of them could be given in 

 the sketch. 



Minerals found are those mentioned above, none of them presenting 

 any very fine crystals, mostly massive. Their character is such as to 

 insure a very rich yield of silver wherever they occur, if even only in 

 small quantities. 



A tunnel 325 feet in length leads to the vein, which is worked upward 

 and downward from it, having reached at the time a deptli of 83 

 feet below the tunnel-level. Every indication of persistence is shown 

 by the lode at that inconsiderable depth, and also upward as far as it 

 has been worked. In consequence of the advent of the Elkhorn, this, 

 mine shows more complicated workings than most of that section. 

 Kear the Pelican are quite a number of other lodes, some of which were 

 not in operation, while a lack of time forbid a visit to any but the prin- 

 cipal ones. West of it still, on Mount Sherman, is an interesting vein, 

 the Cold Stream lode, striking north. 67° west, into a dip to the north, 

 varying from 10° to 25°. The foot- wall on the south side is gneiss, 

 while the hanging-wall is composed of porphyritic granite. This is one 

 of the few instances where the vein showed itself to be a true contact- 

 vein between these two rocks. Some distance from the tunnel, proba- 

 bly 60 feet, the vein is suddenly cut off by a strip of gneiss running 

 across it at right angles, but ap])ears again on the other side without 

 being deflected "the least in its course. Galenite, with sphalerite, com- 

 pose the main ore of this lode ; the former occurring in a heavy body, 

 coarse-grained, breaking into large cubes. Owing to the foot-wall, the 

 vein wavers slightly, forming a sort of scalloped line. West of the tun- 

 nel, a dike of asli-gray porphyry, 6 feet in thickness, crosses the vein, 

 but after working through it was found to continue in its regular 

 course. 



Of minerals, the following are found : galenite in fine cubo-octahedra, 

 sphalerite, argentite, fahlerz, pyrargyrite, wire-silver, with the excep- 

 tion of the latter all occurring massive ; the pyrargyrite and fahlerz inti- 

 mately associated with the galenite; quartz and light-red feldspar, mostly 

 decomposed, make up the gaugue-rock. 



One of the largest and best known lodes of the district is the Terri- 

 ble, located about four miles west of Georgetown, on the south slope of 

 Brown Mountain. It strikes north 82° east; an abnormal course, com- 

 pared with the others. In speaking of the relation of these lodes to 

 the formations surrounding them, it has been stated above that the 

 porphyritic granite formed a steep bluff, running almost parallel with 

 the local trend of the mountain. It is within this granitic bluff that the 

 Terrible vein lies. A tunnel of about 310 feet has been driven at right 

 angles to the lode from the south side, and on the north of it the rock 

 has been examined for the distance of 60 feet. The entire tunnel, as 

 well as the 60 feet beyond it, were found to be within the limits of the 

 porphyritic gTanite. Keeping its course quite regularly-, the ore-vein 

 runs along within the heart of this immense granite dike, varying in 

 thickness and local dip, without any well-defined walls to limit its 

 extent. Numerous little slides have evidently occurred, occasioning the 

 formation of slickensides and breaks in the granite, but no distinct 



