150 ALASKAN MINERAL RESOURCES IN 1905. 
short distance. The vein has not filled the crevice in which it was deposited, so that 
combs are formed by the intergrowth of quartz and cassiterite crystals, the latter reaching 
an inch in diameter. Many of the crystals have been sheared by a slight movement that 
has taken place along the vein. The limestone is much metamorphosed for about 4 feet 
on each side of the vein, and is somewhat impregnated with cassiterite, though to what 
extent is not known. During 1904 a few tons of ore were extracted from this vein and 
shipped to Seattle. 
Another vein occurring a few rods northeast of the one just described is about 4 inches 
thick, strikes N. 20° E., with a vertical dip, and has been traced between 200 and 300 feet. 
It is composed of slender quartz crystals forming interlocking combs. On the quartz 
crystals and sometimes embedded in them are small crystals of cassiterite, occurring singly 
and in small masses, showing that more of the cassiterite was deposited in the later than 
in the earlier stages of the vein's formation. Some of the crystals are beautifully iridescent. 
There are traces of copper and wolframite, and a small amount of lithia mica occurs in 
the vein (specimens T5AH67, T5AH68). 
On the hill between Lost River and Cassiterite Creek is a third vein about a quarter of 
a mile southwest of those already described. It is from 1 inch to 6 inches thick, dipping 
30° S. 10° W., and has been followed by an open cut about 30 feet along the strike and 
10 feet along the dip. The quartz and cassiterite are rather finely crystallized and fill 
the vein with a banded structure. There is also a small amount of iron pyrite, arseno- 
pyrite, and lithia mica, with occasional copper stains in the vein. 
The limestone is much altered for several feet on each side of the veins, and whether 
they will pay to work seems to depend largely on how much tin is carried in the altered 
limestone accompanying them. Should the dike deposits be mined, at least the first- 
described vein would probably pay if worked in connection with them. There seems 
little doubt that these veins can be traced to the rhyolitic dikes in the neighborhood. 
No tin-bearing veins have yet been found in Tin Creek valley, although some float 
pieces of tin ore are said to bave been found. Pyritifcrous granite collected by Collier 
and the writer was shown to carry a small amount (0.3 per cent) of tin,« but whether it 
occurs as an oxide or sulphide (stannite) is not known, as the determination used & would 
not show in what form the tin occurred. 
A small amount of galena, by no means in paying quantity, and some pieces of " moun- 
tain leather,"' a matted form of tremolite asbestos, were found with decomposing calcite 
veins near the granite boss on Tin Creek. Float from another vein about 2 inches wide 
was determined by Schaller as diaspore, a hydrate of alumina. 
Prospecting is being done for galena about 5 miles from the mouth of Lost River, but 
as the shaft was said to be full of water at the time it was not visited. 
CAPE MOUNTAIN AREA. 
On Cape Mountain prospecting for tin has been carried on since 1902, and a large amount 
of work has been done, especially by the Bartells Tin Mining Company. It is a particu- 
larly bleak, inhospitable portion of the country, and the determination and endurance of 
Alaskan prospectors is exemplified in the men who are attempting to open up the tin 
mines in this district, and this applies with equal force to Buck Creek and only in a less 
degree to Lost River. Fine pieces of float tin ore made up of quartz, tourmaline, and 
cassiterite were found at many places in the vicinity of Cape Mountain, but it was not 
until 1904 that the ore was found in place. During 1905 there were further discoveries 
of tin ore that made the outlook more encouraging. 
" Collier, A. J., The tin deposits of the York region, Alaska: Bull. U. S. Geol. Survey No. 229, 1904, 
1>. 22. 
b Idem, p. 43. 
