234 GEOLOGY AND GOLD DEPOSITS OF THE CRIPPLE CREEK DISTRICT. 
are the Portland, Stratton’s Independence, Gold Coin, Hull City Placer (Independ¬ 
ence Consolidated), Isabella, Mary McKinney, Moon-Anchor, and perhaps the 
Victor. To this list should probably be added the C. O. D. mine. Even these 
records do not accurately fix the original water surface, for the Blue Bell tunnel, 
as will be seen, began to drain the district at a very early stage in mining develop¬ 
ment. The mine records show, however, that a former water surface, probably 
not very different from the original water surface, stood from 9,489 to 9,723 feet 
above sea level. As might be expected from the fact that the general slope and 
drainage of the region are westward, the higher water levels were found in the 
eastern part of the district, where the Hull City Placer reached water at 9,723 
feet, the Victor at 9,613 feet (reported), and the Isabella at 9,550 feet, indicating 
a water surface at an average elevation of approximately 9,600 feet. In the 
southern and western parts of the district the Gold Coin reached water at a level 
of 9,396 feet, the Portland at 9,452 feet, Stratton’s Independence at 9,569 feet, the 
Moon-Anchor at 9,489 feet, and the Mary McKinney at 9,498 feet. As the Gold 
Coin mine is entirely in the granite it may be omitted from the present comparison. 
The records of the other mines indicate the former presence of a water surface 
about 9,500 feet above sea. So far as they go, those elevations of “first water” 
that can be accepted as defining approximately the original water surface indicate 
that in the area since extensively opened by underground workings this surface 
sloped westward at a lower angle than the general inclination of the country. If 
the underground water surface had been reached by several shafts before the 
initiation of tunnel drainage, its angle of slope would probably have been found 
even lower. It may be noted in this connection that the 9,500-foot contour (PI. I, 
in pocket), which corresponds to the average elevation of the ground-water surface 
in the southwestern part of the developed area, extends from Wilson Creek, south 
of Victor, around the southwest base of Squaw Mountain to the Economic mill, 
thence to Arequa, thence around Beacon Hill just above the El Paso mine, thence 
to Anaconda, and thence to the’ southeast corner of the town of Cripple Creek. 
This sinuous line lies in general outside of the main contact between the breccia 
and the old granites, gneiss, and schist. It enters the central breccia area, however, 
at Arequa and Anaconda. 
The depth at which water was reached varies from 910 feet in the Isabella to 
35 feet in the Mary McKinney, the latter mine being only a little over 33 feet above 
the 9,500-foot contour at Anaconda. 
As the shafts were deepened, the ground water interfered seriously with mining 
development, and several mines began pumping about the year 1895. It was 
soon found that the cost of lowering the water in this way was a serious burden 
and that it fell chiefly upon a few of the deeper and wetter mines. Such individual 
pumping also revealed certain peculiarities of the ground water which will be 
referred to later. Attention was accordingly turned to tunnel drainage. 
