470 GEOLOGY AND GOLD DEPOSITS OF THE CRIPPLE CREEK DISTRICT. 
are usually at those points where the “basalt” cuts across the phonolite. On 
level 9, at the time of visit, the north ore shoot had been found and had been drifted 
on for about 200 feet. Stoping had not begun, however, on this level. 
The mineralization of the granite in the north pay shoot is not related to such 
distinct parallel sheeting as is observable in the south pay shoot. The ore-deposit¬ 
ing solutions apparently worked outward from the narrow channels furnished 
by the platy partings and contact planes of the dikes and took advantage of such 
small irregular cracks and joints as existed in the granite. The granitic ore is 
usually rather spongy in texture, closely resembling that from the Diamond lode 
in the Portland mine or from the large southwest stope in the Ajax mine. Con¬ 
trary to the practice in most of the mines in the district, very little assaying is 
done in the Strong mine, the ore usually being readily distinguished from the 
county granite by its color and greater porosity. 
CHARACTER OF ORE. 
The ore of the Strong mine is almost entirely metasomatically altered granite. 
Rounded residual kernels of the original pink microcline of the granite remain, but 
the quartz and biotite have been completely changed to a porous aggregate of 
adularia, quartz, fluorite, pyrite, and calaverite. The adularia is easily distinguish¬ 
able under the microscope from the original microcline by its greater clearness and 
frequent sharply automorphic outline. The secondary leklspar is often optically 
continuous with an older individual of microcline, the two being separated by a sharp 
sinuous line. The tiny crystals of adularia are rarely optically homogeneous, but 
appear to be built up of wedge-like or sector-shaped portions that extinguish at 
slightly different angles, and produce an optical effect similar to that often observed 
in thin sections of vein quartz and illustrated in the quartz of this same ore. The 
quartz in the Strong ore occurs in allotriomorphic grams cn^stallized with the 
secondary feldspar and as a crystalline film lining the little irregular vugs of the 
porous altered granite. Fluorite is not very abundant in the ore; it occurs usually 
as little implanted crystals in the vugs or in minute fissures in the original microcline. 
Pyrite occurs abundantly disseminated in minute crystals through the secondary 
minerals of the ore, and these crystals are sometimes gathered into little nests or 
bunches. Calaverite seems to closely accompany the pyrite and occurs in such 
minute particles that it can rarely be detected or distinguished from the pyrite 
even with a hand lens. No oxidized ore is now worked in the Strong mine. 
UNDERGROUND WATER. 
According to an estimate made by Mr. V. G. Hills,° in July, 1903, the water level 
in the Strong mine, were pumping discontinued, would stand at 8,984 feet above 
sea level, or 771.99 feet below the collar of the shaft. At that time, however, it 
was kept down by pumping to 8,872 feet, or 883.99 feet below the collar. The 
water was held at this point and level 9 kept open by pumping about 500 gallons 
a minute. In April, 1904, this amount had decreased to 330 gallons. The greater 
part of this water comes from the northern part of level 9. Xo data exist 
a Ninth Ann. Kept. Portland Gold Mining Company, 1903, p. 87 
