MINES OF RAVEN AND GUYOT HILLS. 
341 
pvrite and is probably molybdenite. Within the thicker portions of some of the 
irregular sdpta of the sponge-like mass of residual particles of phonolitic breccia 
not transformed to adularia. Probably some calaverite or sylvanite is present, 
but it is not microscopically distinguishable from the pyrite. Quartz seems to 
be entirely absent, except in the form of little hollow pseudomorphs after celestite 
in some of the open pores of vugs. This material is a local metasomatic alteration 
of the breccia along zones of Assuring and shattering, the spongy mass passing 
, gradually into breccia in which fragments of phonolite are still recognizable. 
The occurrence of phonolite ore is best illustrated in the flat stopes on level 7. 
This ore is a light-gray rock abundantly speckled with minute crystals of pyrite 
and flecked with purple fluorite. It is characterized by a rather porous texture, 
due mainly to the existence of small very irregular spaces of dissolution. The 
origin of these cavities is not always clear. In many instances, however, they 
are enlargements of minute fissures and particularly of several fissures at points 
of intersection. In other cases they are probably due to the removal of ampliibole 
or pyroxene plienocrysts and the subsequent irregular enlargement of the cavity. 
Occasionally these spaces are entirely filled with fluorite. More often, however, 
they are only partly filled with projecting crystals of fluorite, quartz, pyrite, and 
probably calaverite, though the last-named mineral can scarcely ever be distin¬ 
guished by the eye from the bright crystals of pyrite abundant in these little vugs. 
Under the microscope, although small crystals of pyrite are abundantly dis¬ 
seminated through the rock, and though the original pyroxene or ampliibole phe- 
nocrysts have been replaced by fluorite and pyrite, the feldspathic portion of the 
phonolite shows remarkably little alteration. 
Very little oxidized ore is now seen in the Elkton mine. In the Thompson 
workings the granitic ore is more or less oxidized to a depth of about 300 feet. 
No particular difference in value has been noticed between the oxidized and unoxi¬ 
dized ore. Generally throughout the mine there is very little oxidation below the 
300-foot level. 
UNDERGROUND WATER. 
The occurrence and behavior of the underground water of the Elkton mine 
have been fully described in the section devoted to the underground water of the 
district. (See p. 242.) It has been one of the wet mines and the history of its 
water is closely connected with that of the Standard and El Paso tunnels. 
MOOSE MINE. 
INTRODUCTION. 
The Moose mine is situated on the southeast slope of Raven Hill, about half 
a mile northeast of Elkton. The mine is owned by the Moose Gold Mining Company, 
incorporated in 1893, with a capital of $1,200,000. The company owns the Moose 
claim and leases portions of adjoining claims, including the Bertha B. and Kentucky 
Belle. The Trilby mine, also owned by this company, is elsewhere described. 
The Moose was one of the first mines in the district to become productive, 
and up to the end of 1896 made steady shipments of rich ore, the average value 
for considerable periods being nearly $140 per ton. In 1897, however, the ore shoot, 
