KANso.ME.] FAULTING AS AN ACCOMPANIMENT OF FISSUEING. 55 
Search was made in Cunningham Gulch, along the Uncompahgre, 
and at other points for any evidence of the diversion of fractures and 
mineralizing solutions along the contact of the older schistose terrane 
with the volcanic series, but with negative results. 
Lines of Assuring in this region are occasionally determined by 
igneous dikes. Thus the Magnolia, a superficially prospected north- 
west-southeast lode just northeast of Silver Lake, follows for some 
distance an andesitic dike about 6 feet wide which curves across the 
gulch toward Round Mountain. Both this dike and a larger one 
which crosses it are irregularly fissured and traversed by poorly 
mineralized quail/ stringers along the greater part of their exposed 
lengths. A similar occurrence was noted on the south side of Ken- 
dall Gulch about a mile a little east of south from Kendall Moun- 
tain, where a vein about 6 inches wide lies on the south side of a 
nearly east-and-west andesitic dike. None of these fissures have yet 
proved of much economic importance. 
displacement or faulting as an accompaniment of the 
fissufjx<;. 
Iii a few cases only, and those of relatively unimportant lodes, has 
tangential dislocation been detected as a consequence or accompani- 
ment of the original Assuring. The abandoned Moles mine, 3 miles 
south of Silverton, is on a vein about 2 feet wide which apparently 
rills a fault fissure of noticeable throw. The head of Deer Park 
Creek is crossed by a nearly north-and-south fault, with the down- 
throw on the west side, which is accompanied by some brecciation 
and veining of the schists along the fracture and with unimportant 
mineralization. 
On the eastern side of Iron ton Park, as shown in the Saratoga and 
Baltic mines, the formation of a parallel series of approximately 
northeast-southwest fissures has been accompanied by obvious fault- 
ing. These fissures, as a rule, dip steeply to the southeast. In all 
cases where it could be made out the faulting is normal, and the 
maximum throw, as observed on the Mono vein, can hardly be less 
than 100 feet. This fissure carries a body of low-grade pyritic ore. 
In the northeastern portion of the quadrangle the field work of 
Messrs. Cross and Spencer appears to demand considerable faulting 
along some of the prominent vein fissures. But as there are no exten- 
sive underground workings in this portion of the area the evidences 
of such faulting did not come under my observation. 
Notwithstanding the foregoing exceptions, it remains true that such 
displacement as occurred in connection with the formation of most of 
the principal productive lodes was slight in amount, although proba- 
bly not wholly absent. Moreover, the peculiar branching arrange- 
ment of many of the fissures, described on page 52, and their disposition 
en echelon, as in the Silver Lake and Iow^a mines (p. 157), would seem 
