collier.] REPORTED LODE DEPOSITS. 25 
have been mistaken for cassiterite. A sample assayed for tin by Mr. 
Sullivan, of the Survey, contained a trace of tin, a few hundredths of 
1 per cent. The principal constituent is tourmaline, in slender black 
or brown needles, and wolframite or scheelite are probably present, 
if, as reported, a considerable amount of tungsten was found. 
Tin ore was discovered on Cape Mountain in Juty, 1902 v by Mr. 
W. C. J. Bartels. In the fall of 1902 he brought out a large collection 
of specimens, which on examination by chemists and assayers, was 
found to include some tin ore. Extensive developments were planned 
for the season of 1903, and a well-equipped prospecting plant was sent 
to Cape Mountain. A large dynamo driven by a gasoline engine was 
to be placed near the beach at the point now known as Tin City, and 
from this dynamo wires to several points on the mountain were to 
supply power for electric drills. By the use of these drills it was 
expected that tunnels could readily be extended into the heart of 
the mountain and crosscut the ledges from which has come the float 
ore. 
After spending nearly the whole of the season of 1903 in getting 
the machinery in place and establishing the winter camp it was found 
that the engine for driving the dynamo was defective, and the plan 
for development work during the winter of 1903-1 was necessarily 
suspended. 
No work is now in progress on Cape Mountain, so far as is known, 
and very little advance has been made in revealing the nature of the 
ore deposits since the float ore was first discovered. This work, how- 
ever, will undoubtedly be resumed in the summer of 1904, and it is to 
be expected that by the end of that season more definite information 
will have been obtained. 
LOCALITIES FROM WHICH LODE TIN HAS BEEN REPORTED. 
The discovery of tin ore in ledges has been reported by prospectors 
from many other localities in Seward Peninsula, some of which deserve 
notice, since the geologic conditions are known to be promising, and 
they will be described in some detail. 
DIOMEDE ISLANDS. 
These islands, which lie in Bering Strait, midway between Alaska 
and Siberia, are reported to be composed of granite, though they have 
not been examined by geologists. It is probable that they represent 
an intrusion similar to that at Cape Mountain. It is reported that 
copper ore has been found on them, and should the tin ore found on 
Cape Mountain develop commercial importance they may merit 
investigation. 
