GOLD DEPOSITS OF THE SHUMAGIN ISLANDS. 
By George C. Martin. 
APOLLO CONSOLIDATED MINE. 
Locution and out pat. — The Apollo Consolidated mine is situated 
near the southern end of Unga Island, about 3 miles west of the town 
of Unga and 1 mile west of the head of Delarof Harbor. The post-; 
office is Apollo. The mine has been producing since 1801, and has 
yielded a total of between $2,000,000 and $3,000,000. 
Previous work.— The occurrence was described by Becker a in 1898. j 
The writer visited the mine in 1904, and gathered a few additional 
facts concerning the occurrence and the geology of the region. 
Character. — The deposit is described by Becker as a reticulated veirl 
or zone of fracture in a large mass of andesite and dacite. The ores 
consist of free gold, pyrite, galena, zinc blende, copper pyrite, and* 
and native copper. The ore is free-milling, a large part of the gold 
occurring in the native state. The gangue minerals are quartz and 
subordinate amounts of calcite and orthoclase. The ore body strikes 
N. 4:3° E. and is, in general, vertical. It is from 5 to 40 feet wide ancj 
forms a shoot that pitches northward. The southern end of the shoot 
comes to the surface at an elevation of 600 feet at the present south- 
ern limit of the workings, and narrows and becomes of low grade at 
the northern end at a depth of about 800 feet. An attempt is now being 
made to reach the ore body at lower levels by a shaft and tunnel. 
The best ore bodies are said by the management to occur wherever 
two diagonal sets of fractures intersect. The profitable ore is said to 
carry from $1 to $50, averaging perhaps $8. 
The country rock has been mineralized to a certain extent on either 
side of the main ore body, and smaller and less rich ore bodies parallel 
to the main one are known. 
Age. — Regarding the age of the deposit, Doctor Becker concludes 
that the country rock is Miocene or post-Miocene, from its lithologic 
similarity to andesites, which are supposed to overlie the Miocene at. 
the north end of the island. He would accordingly make the mineral 
veins of very late Tertiaiy of post Tertiary age. 
The writer has observed that some at least of the andesites at the 
north end of the island are apparently below the Tertiary sediments 
either by unconformity or by intrusion. He furthermore believes 
that lithologic similarity of the andesites is an insufficient basis for an 
a Becker, G. F., Reconnaissanci of the gold fields of southern Alaska: Eighteenth Aim. Kept. U.S. 
Geol. Survey, pt. 3, pp. 12, 83-85. 
100 
