178 GEOLOGY AND GOLD DEPOSITS OF THE CRIPPLE CREEK DISTRICT. 
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water which in 1901 flooded the lower levels of the mine. This, as diagram- 
matically sketched in fig. 12, is a lateral offshoot from the Elkton lode at a point 
where the breccia had been locally shattered. Apparently the finer fragments 
were partly removed in solution, and the larger ones and the walls of the irregular 
cavity were coated with crystals of quartz and fluorite, which in part were accom¬ 
panied by tellurides. In this case the fluorite is not merely a coating on the frag¬ 
ments which partly filled the cavity, but has to some extent metasomatically 
replaced them. 
The crystalline crusts which coat the walls of the fissures seldom show well- 
defined continuous banding such as is often found in crustified veins of greater 
width and of more abundant filling. ‘ The development of such a structure requires 
a fairly definite mineralogical sequence or paragenesis and fissures of greater average 
width than those of Cripple Creek, so that the crusts as successively deposited will 
be thick enough and continuous enough to be distinctive in spite of minor irregu¬ 
larities of crystal growth. Fairly regular banding was noted, however, in the 
Galena mine, the order of crys¬ 
tallization being (1) quartz, ga¬ 
lena, and sphalerite; (2) radial 
pyrite; (3) sphalerite; and (4) 
fluorite, rhodochrosite, and 
sphalerite. A rather indistinct 
banding of quartz and fluorite 
was observed also in t he C. K. & N. 
vein, on level 4 of the El Paso 
mine. The Mary McKinney lode 
is apt to show a sharply defined 
filled central vein. A specimen 
of one-half of the vein, 3 inches 
in thickness, shows that the dep¬ 
osition began by two narrow 
fluorite bands separated by a 
narrow quartz seam. On top of the second fluorite band calaverite crystals are 
deposited; then follow mixed quartz and fluorite coated by thin, yellow opal and 
cryptocrystalline chalcedon}^. 
The Gold Coin vein, on level 12, shows distinct banding. Next the wall is 
deposited quartz with pyrite, zinc blende, and galena; then follows 3 mm. of solid 
comb quartz covered by a drusy mass of crystallized quartz and fluorite. Idle 
Puzzle vein in a similar manner shows crusts about 1 inch thick, consisting of zinc 
blende and galena covered by a quartz crust on which slender crystals of calaverite 
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fSSsliSi 
V/.Breccia .■<?\ 
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Fig. 12.—Sketch section across expansion of vein on level 7, Elkton 
mine, looking north 
appear. 
In general, then, the typical vein of Cripple Creek consists of one or more 
fissures ranging from 1 to 6 inches in width, whose walls are lined with crystalline 
crusts of quartz, fluorite, or dolomite. Along parts of the vein the crusts are thick 
enough to meet and the vein is solidly filled with tellurides and gangue, but in most 
parts the medial line of the vein is open or vuggy, and the crystals of calaverite or 
sylvanite project with crystals of the gangue minerals into the vugs. In many 
