collier.] CHARACTERISTICS OF TIN ORE. 39 
and concentrating, but, obviously, during the winter this source of 
power is cut off, and coal or other fuel must be used. In Alaska there 
are two possible sources of coal for the York region. One of these 
is near Cape Lisburne, rt about 200 miles northeast of York, on the 
shore of the Arctic Ocean. There is reported to be an abundance of 
coal suitable for steaming purposes at this place, but there are abso- 
lutely no harbor facilities and there is no wood available for timbering 
the mines, and, further, navigation on the Arctic Ocean is possible 
for only two months of the year; so that these coal beds can not be 
depended on to furnish a coal supply. 
The other source of coal is at Herendeen Bay and Port Moller, 
about 700 miles to the south, on the Alaskan Peninsula, but this coal 
has not been sufficiently developed to determine whether it exists in 
commercial quantities. At the present writing it seems that the only 
certain sources of fuel for the Seward Peninsula are the coals of 
the State of Washington and those of British Columbia. On account 
of the difficulty in obtaining fuel and the cost of labor and subsistence 
in the Seward Peninsula it does not seem possible that the smelting of 
tin ore in the York region will ever be successfully accomplished. 
The ore from this region will necessarily be shipped either to the coal 
mines in other parts of Alaska, to Puget Sound, or to other points for 
smelting. The freight on ore shipped from Port Clarence to Seattle 
would probably be very low, since the large number of vessels carry- 
ing freight to Seward Peninsula and St. Michael would desire return 
cargoes. 
In the summer of 1902, 98,822 tons of freight were carried to these 
points. 
TIN ORES AND ASSOCIATED MINERALS. 
Physical characteristics of tin ore. — Cassiterite, tinstone, or tin ore, 
the dioxide of tin, is the most common form in which tin occurs in 
nature. It crystallizes in four-sided prisms and octahedrons, but 
twinning is so common that simple crystals are rarely found. The 
stream tin of the York region usually occurs in rounded pebbles, its 
color varying from light brown to black; the color of the streak — 
that is, of the powdered mineral— is pale gray to brownish. Wood tin 
is cassiterite that occurs in botryoidal and reniform shapes, with con- 
centric and radiated hbrous internal structure, though very compact. 
Its color is brownish in varying shades, which give it somewhat the 
appearance of dry wood. A few specimens of wood tin have been 
found on Buck Creek. Cassiterite has no distinct cleavage visible to 
the naked eye. It has about the same hardness as quartz, but is very 
much heavier, having a specific gravity, when pure, of from 6.4 to 7.02. 
"Schrader, F. C, A reconnaissance in northern Alaska in 1901: Prof. Paper U. S. Geol. Survey No. 
20, 1904, pp. 109-114. 
