44 ALASKAN MINERAL RESOURCES IN 1905. 
sited between GOO and 800 feet elevation, and consist of open cuts and a tunnel SO feel in 
length. Many other prospects have been located along the east coast of Dall Island, 
though no improvements of importance have been made on them. 
GRAVINA ISLAND. 
The Gold Stream group of claims, generally known as the Miller mine, is situated close to 
tide water on the east side of Gravina Island, about 3milesfrom Ketchikan. The surround! 
ing rocks are principally schistose greenstones (PI. XI). Mineralization has followed certain 
bands of this schisl country rock, impregnating it with auriferous sulphides and altering it 
to a talcose and siliceous schist. Two lodes of this character averaging (> and 40 feet in 
width have been opened by developments. On the smaller or easternmost lode a shaft 100 
feel deep has been sunk, from which 300 feet of drifting have been extended and about 1 ,30i 
ion- of ore mined. At the upper, larger lode a .10-foot shaft has been sunk and its surface 
exposures invest igated by trenches. A 5-stamp testing mill equipped with a concentrating 
table is on the property, and encouraging results are reported. 
REVILLAGIGEDO [SLAND. 
At ( reorge [nlet, which forms one of the deep-water fiords on the southwest side of Revil- 
lagigedo [sland, several prospects have been discovered which give promise of future value 
if properly developed. Near the cut ranee of I he inlet the Surprise group of claims has been 
located on several low-grade gold-bearing veins. Adjoining these claims on the north is the 
Londevan group of claims, originally known as the Telegraph group. At its south end 
six parallel quartz veins occur, striking north and south with the black argillite country 
rock and dipping at low and variable angles to the northeast. They can be followed along 
the surface for several thousand feel and vary from 1 loot to 5 feel in thickness. They are 
said t.» carry hi:_ r h silver and low gold values. I\ 'rite, galena, and zinc blende, with quart! 
and calcite as gangue minerals, are the most important minerals contained in the veins. At 
the north end of the property the entire series of veins apparently merges into one huge 
quartz vein, which is of low grade and somewhat different in character. 
The Sea Level mine and adjoining properl ies are located near t he head of Thome Arm, a 
bay south of George Inlet. Several years ago mining developments were pushed vigorously 
at the mine and notable improvements made." Since 1903, however, assessment labor 
only has been done and at the time of visit I he property was idle. Several of the properties 
in this vicinity have good free-gold surface showings and may prove valuable if propers 
developed. 
CLEVELAND PENINSULA 
Helm Bay (ills a deep indentation on the southwest end of Cleveland Peninsula and follows 
closely the si ructural lines of the underlying rocks. On the east side of the bay a wide belt 
of folded argillites and altered slates is exposed, while on its west side is a complex of green- 
stone schists, trending parallel to the shore line and composing the mountain ridge, 1,000; 
to 2,500 feet in elevation, to the east. These schists contain the only workable deposits 
which have been discovered on the peninsula. Mineralization is widespread in the schist 
series and low values in gold are not uncommon. Local rich pockets of gold-bearing quart! 
have been discovered at several points and nntied with great activity for a short time. Of 
late years, however, little work has been accomplished on the peninsula, the attention of 
prospectors having been directed to other and newer camps. Sufficient labor, however, has 
been expended on these veins to show thai they are a mining possibility and that the average 
content of the veins should he emphasized rather than the occurrence of rich and alluring 
bonanzas. The gold occurs both as free gold and with pyrite, also in small quantities as 
gold telluride. The chief prospects of the bay are the Gold Standard group, the Gold 
Mountain group, the Alexandria, the Old Glory, the Starry Banner, the Last Chance, and the 
" Brooks, A. II., The Ketchikan mining district, Alaska: Prof. Paper IT. S. Geol. Survey No. 1, L902, pd 
r,(\ 68. 
