428 WEED AND PIRSSON 
stained a rusty color by iron. Inmost of the ore free gold is 
seen in small spongy masses of a dark coppery color. 
The slight amount of development work as yet carried on 
makes any conjecture as to the mode of occurrence of the ore 
bodies quite hypothetical. The total absence of dikes, and the 
fact that.no contact deposits have been found, points to the 
origin of the deposits as due to the alteration of shattered zones 
of the porphyry itself. That there has been some movement 
and fracturing of the porphyry since its consolidation is proven 
by the slickensided surfaces seen near the Alabama mine. The 
presence of fluorite may have some connection with the telluride 
ores which are the source of the gold. In the mines of the 
Judith Mountains the richest ores occur associated with fluorite, 
and the source of the) tree yold tseems, to hayes bcenmthientel: 
luride minerals. This association of fluorite with gold has been 
noted by various observers at Cripple Creek and in Boulder 
county, Colorado." 
The Goldbug mine is the only property which shows any con- 
siderable amount of development. It is owned by G. L. Man- 
ning and the heirs of Pike Landusky. It was bonded some years 
ago to the owners of the famous Granite Mountain mine, but 
was relinquished and is now bonded by another syndicate, who 
are having the ore body prospected, under the superintendence 
of M. H. Jacobs, formerly of Hailey, Idaho, whose many cour- 
tesies are here gratefully acknowledged. The Goldbug claims 
are located upon the breccia and shattered porphyry, whose 
crushed condition permitted the ready passage of mineralizing 
waters acting upon the feldspathic and basic constituents of the 
rock, replacing them and filling the seams with quartzose mate- 
rial which is gold bearing. 
WaLTER Harvey WEED. 
Louis V. Pirsson. 
WASHINGTON AND NEW HAVEN, 
April 1896. 
*Mining Geology of the Cripple Creek District, Colorado, by R. A. F. PENROSE, 
Jr., 16th Annual Report of the Director of the U. S. G. S., Vol Il, Washington, 1896. 
