colliek.] KECENT DEVELOPMENT OF TIN DEPOSITS. 125 
cuts has been done to locate the lode. This locality is near the con- 
tact between the limestone and a large offshoot from the main granite 
mass. Probably none of the rich ore has been found in place, though 
one of the prospect holes shows a thin seam of tourmaline similar to 
that associated with the tin ore in the contact between the granite 
and limestone. 
The prospecting on this mountain has unfortunately been done 
mostly on the surface and at many scattered places, usually as assess- 
ment work, merely to hold the various claims; consequently the devel- 
opment of possible veins or lodes has not been commensurate with 
the work done. In only one case has ore containing more than traces 
of tin actually been found in the bed rock, and further work will be 
required to demonstrate whether or not ore bodies of commercial 
value exist. 
BROOKS MOUNTAIN PROSPECTS. 
Considerable prospecting for. tin was done on the surface of Brooks 
Mountain, which is located about 5 miles north of the Lost River local- 
ity, and lode deposits similar to those at Lost River are reported to have 
been found. The locality has never been examined in detail by the 
writer, but specimens of ore that were reported to have been found 
bere were seen at Nome. This ore is similar in character to that 
obtained from the altered porphyritic dikes of Lost River. 
EARS MOUNTAIN PROSPECTS. 
Ears Mountain is located about 60 miles northeast of Cape Prince of 
Wales and 50 miles north of Port Clarence. Like Cape Mountain, it 
consists of a granite mass surrounded by slates and limestones into 
which it is intruded. Several parties of prospectors searching for tin 
ores have visited this localhty during the last two years, and many 
specimens of rock supposed to be tin ore have been brought out. 
With one exception, none of these which were examined by the writer 
contain more than traces of the metal. 
DARBY MOUNTAINS. 
Outside of the occurrences noted above, tin ore is not known to have 
been found in place anywhere in Alaska. These localities are all in 
the York region of Seward Peninsula. While the writer was at 
Nome in the early part of the past season, however, a specimen of tin 
ore said to have been found in the region north of Cape Darby was 
referred to him by a prospector who had recently returned to Nome 
from Norton Ray. The specimen seemed to be a piece of granite that 
had enough cassiterite disseminated through it to make up possibly 
10 per cent of its weight. If this tind turns out to be genuine, it will 
indicate a wide distribution of tin- bearing ledges beyond the limits of 
the York region. 
