50 GUIDEBOOK OF THE WESTERN UNITED STATES. 
South Cheyenne Canyon and the form of the mountains in this. 
™ part of the State indicate to the geologist, as already explained, that 
at a time long, long ago this part of the earth’s crust was much nearer 
sea level than it isnow. The mountains of Colorado were not then the 
magnificent spectacles they are to-day but were more like the Ap- 
palachians. Pikes Peak of that time was probably not more than 
5,000 or 6,000 feet above sea level, and the plains reached back many 
the other parts of the contact the 
walls are also steep. e general con- 
clusion reached is that a tremendous 
e 
gern including bits of 
granite litt sch and pieces of the 
trees that were pieces on the plateau 
groups of closely mg narrow fis- 
—o eeted zon 
thPoteH masses of altered granite near 
; g 
= = 
Feet 3 
* SE. 
_ped eee 3 ieamic COne--- Eee é r 
1,000 sours Seo eed Prete = 
a : rl EPI) 
10,0004 | Ae ok eee , 7 rai T 
9,000 - 7 as 
¢ 
& 
= 
¢ 2 
- 
et eM Se ne 3 NNE. 
12,000 2 joaaic Sots ~~, 9 ; 
o Ff VOCS Bl Cliff ~~~. c 
11,000 2 eaeoe ts ou oy te a 
tk Se oe 6.6, Py = faery 
10,000 + __-su. Te a Breccia? ve } 
9,000 LEZ 23 ers iy ae 3EF wh e, 
2 _ 3Miles 
Figur 12.—Sections showing supposed outline of the Cripple Creek volcano. 
at that time. To these materials were 
added, probably by later eruptions and 
shown in figu 
consisting chiefly of fragments of rock 
was built up above the breccia-filled 
abyss. 
After the eruptions had ceased the 
rocks adjusted themselves to the new 
conditions. ks were formed in 
them and in these cracks the gold ores 
were deposited by hot solutions that 
rose from deep volcanic sources. Rain 
and streams gradually wore away the 
cone and exposed the veins thus 
fo Hah which the keen eyes of pros- 
pectors afterward detect 
The gold ores of Cripple Creek oc- 
eur partly aS narrow veils or as 
and tellurium, associated with quartz 
and purple fluorite. Native gold is 
rare, except in the uppe xidized 
parts of the veins. 
ton, but the gold content varies 
wile and comparatively small bodies 
of very much richer ore have been 
mi 
ned. 
In this district, as in most others, 
the ore is not uniformly distributed 
along the veins but is limited to what 
the one found in the C 
like the well-known Pivaan. depend 
mainly upon large shoots of ore of 
