242 
ECONOMIC GEOLOGY OF SILVERTON QUADRANGLE, [bull. 182. 
bo Mr. W. II. Fry, part owner and former superintendent of the 
mines from 3 to 4 ounces of silver and 0.4 to 0.5 of an ounce of 
gold, being thus too poor to work. Several tunnels have been run 
into the hill, but owing to the easterly dip of the ore they all pass 
through the ore body and, if continued far enough, come into the 
volcanic rocks of the Silverton series. This oxidized ore is not capped 
by the overlying andesite, but passes upward into the loose material 
and soil of the present surface of the hillside. When, however, the 
ore is followed far enough to the eastward it passes beneath andesitic 
breccia and changes to a sulphide ore, consisting of pyrite and a little 
chalcopyrite, with occasional bunches of partly oxidized pay ore, car- 
rying galena and argentite. This ore is the result of a replacement of 
the limestone to varying depth along the contact between it and the 
Upper quartzite 
Fig. 22.— East-and-west section through the Saratoga mine. (After G. E. Kedzie.) 
overlying andesitic breccia. It varies in thickness from a few inches 
up to 3 feet. The overlying volcanic breccia is usually much altered, 
thickly impregnated with pyrite, and traversed by veinlets of the 
same mineral. The ore is not distributed at random through the con- 
tact plane between limestone and breccia, but the bunches of ore thus 
far found lie along a line bearing about N. 30° E., as if the minerali- 
zation had been controlled by some fissure or fissures having this 
direction. As this is the dominant direction of Assuring in the vicin- 
ity, this seems not unlikely. The actual fissure which determined 
the mineralization is, however, not readily identified. It may lie to 
the westward, in which case its intersection with the ore horizon has 
been removed by erosion. It may be the large lode, presently to be 
described, which lies to the eastward, or it maybe someTess con- 
spicuous fissure. A small fissure having this strike of N. 30° E. was 
