12 GEOLOGY AND GOLD DEPOSITS OF THE CRIPPLE CREEK DISTRICT. 
being added on the western side, so that the total area mapped is about 40 square 
miles. The small developments outside of this area did not seem to justify further 
extension of the boundaries. Contours are 50 feet apart, and a numbered list of 324 
mines is given on the margin of the sheet. A line of accurate levels w r as run to 
Cripple Creek from Colorado Springs, thus settling the conflicting data of the differ¬ 
ent railroads. A bench mark was established at the National Hotel at Cripple 
Creek, in the south w r all of which an aluminum tablet is set. The height of this is 
derived from a point established by the Colorado Springs and Cripple Creek District 
Railroad, the top of a nail in a cross-tie in front of the station, the elevation of which, 
as corrected in accordance with the adjustment of 1903 by the United States Coast 
and Geodetic Survey at Colorado Springs, is accepted as 9,492.08 feet above mean 
sea level. Dependent on this the elevation of the datum tablet is accepted as 
9,495.136 feet above mean sea level. All permanent bench marks dependent on this 
datum are marked with the letters “CC” in addition to the figures of elevation. 
The datum plane commonly accepted before this accurate work was done, and used 
by Mr. V. G. Hills in his reports on the water conditions in the district, is 7 feet lower, 
so that to obtain the correct elevation 7 feet should be subtracted from his data. 
