28 
GEOLOGY AND GOLD DEPOSITS OF THE CRIPPLE CREEK DISTRICT. 
60°. It may also be well seen about 300 feet southeast of the Burns shaft in a 
crosscut east from the Portland vein. The contact is here sharp, the breccia rest¬ 
ing closely upon an uneven surface of granite. The dip is abnormally low, being 
only about 15°, toward the east. This low dip is undoubtedly local, and if the 
breccia could be removed the granite at this point would probably be found forming 
a relatively flat bench or step with steep scarps above and below. The contours 
of PI. V are strongly indicative of such changes of slope. 
On the 600-foot level the contact, as exposed a short distance north and east 
of the Burns shaft, is definite and close. It is rather irregular, but nearly vertical 
on the whole. Near the Diamond vein, however, about 300 feet east of the shaft, 
the contact is a regular plane dipping about 35° NE. and exhibiting clear evidence 
of some faulting between the granite and the breccia; but the movement is appar¬ 
ently local and not connected with any great displacement. A moderate dip, here 
as on the 500-foot level, obtains on the crest of the granite promontory. It is 20° 
steeper, however, than on the level above, which fact, taken in connection with 
what is known of the contact below, indicates proximity to the outer edge of the 
granitic bench already referred to. 
On the 700-foot level the contact between the granite and breccia is exposed 
in the main drift about 100 feet north of the Burns shaft. It is here sharp and 
close, rather irregular, and as seen in the drift nearly vertical. East of the Burns 
shaft the contact practically coincides with the No. 2 vein. 
On the 800-foot level the contact is in part the east wall of the No. 2 vein. It 
is sharp and irregular in detail. The granite is sometimes shattered for a foot or 
two from the contact, which is here nearly vertical. Toward the north the contact 
soon swings westward, away from the No. 2 vein, and is again well exposed in the 
main northeast crosscut about 125 feet from the Burns shaft. This contact is 
remarkably close and definite and shows no evidence of faulting. Its course where 
cut by the crosscut is nearly north and south and it dips eastward at about 80°. 
On the 900-foot level the contact between the granite and breccia is exposed 
in at least five places. North of the Burns shaft the granite shows some breccia- 
tion near the contact, and the latter is not so sharp and distinct as in other parts of 
the mine. Just east of the No. 2 vein, which is partly within the granite on this 
level, the contact is clearly exposed in a short crosscut. The granite is shattered, 
but not brecciated, for a distance of 2 or 3 feet from the breccia, while the latter 
contains abundant particles of microcline and some small fragments of granite, 
those seen being less than 3 inches in diameter. The contact here dips eastward at 
75° to 80°. A little farther north a crosscut west of the No. 2 vein, which is here 
wholly in granite, exposes a close, definite, irregular, vertical contact of the latter 
rock with the breccia. 
On the 1,000-foot level the contact is exposed about 100 feet north of the 
Burns shaft and along the No. 2 vein. In general it is approximately vertical and 
presents characteristics similar to those observed on the level above. 
The granite-breccia contact is hardly so well exposed in the Independence 
workings as in the Portland. In general it is fairly distinct on the upper levels, 
the granite, as a rule, not showing much brecciation in its vicinity. In detail it 
is exceedingly irregular, being diversified by minor salients and reentrants. The 
