NORTH-WESTERN DISTRICT (No. 1).

some distance from the surface. Local irregularities were observed in the bed-rock floor near the
placer-gravels and similar variations may also be expected at the claims. It appears that these placers
might be exploited by dredging, but large boulders are likely to be encountered.

South Fork.—Near the headwaters of South Fork, below Sulphide creek, a second group of claims
has been located 16 miles above its junction with the Unuk river, on veins within the sedimentary belt
east of the Coast Range granite. These claims were not visited by the writer. Well-defined deposits
are reported and plans for future development are contemplated.

Boulder Oreek.—Below South Fork on the same side of Unuk river prospects have been located
on similar veins near Boulder creek, a glacial stream, about 10 miles in length and rising near the
Coast Range contact.

North Fork.—The territory drained by North Fork and by Glacier creek, two glacier-fed streams
reported to be about 15 and 18 miles long respectively, has not been prospected systematically. The
ore-bodies which have been discovered are similar to others in this belt, and are frequently rich in
galena, with good values in silyer. The same statement applies to the region near the headwaters
of Unuk river.

Canyon Creek.—In the vicinity of Canyon creek several ore-bodies have been discovered, and are
significant because of their close proximity to the granite-contact along which Canyon creek has cut
its course. The principal prospects near Canyon creek are the Black Bear claim and the Daily Boy
group. The first is located on a vein 2 feet wide, outcropping along the selvage of a diorite-porphyrite
dyke, and contains auriferous pyrite and pyrrhotite. The Daily Boy group is located in a gulch
adjacent to Canyon creek, on veins occurring in altered black slates, argillites, and quartzites. The
entire assemblage of strata is folded and faulted considerably and is characterized by intense induration
and mineralization by sulphides, especially pyrite. On weathering they often become covered with a
deep brown crust of ferruginous compounds, not unlike brown paint in appearance. The complex is
cut by lamprophyrie dykes of variable width and loose contact selvages. The veins which have been
discovered in this gulch contain, besides pyrite, pyrrhotite and occasionally galena and sphalerite.
No development-work of note has been done on either of these prospects.

Summary.

The geologic cross-section exposed by the Unuk River valley, across part of the Coast range,
consists of two parts; on the west, a wide belt of Mesozoic granitic masses, formed during the same
general pericd and grouped into one great unit, the Coast Range batholite, which on the east intrudes
partially metamorphosed and probably Paleozoic sedimentary rocks in which ore-deposits have been
discovered. A discussion of the type of metamorphism of this rock-complex leads to the inference that
its metamorphic changes were largely due to the contact action of the jntrusive granite; that the
impregnation of these rocks by metallic sulphides was essentially concomitant with their contact
metamorphism; that at the time of the granitic invasion this sedimentary belt was nearer the surface
than the invaded strata on the coastal side of the batholite; and that the different physical conditions
resulting from differences in relative position to an intrusive are important factors in determining not
only the type and intensity of metamorphism, but also the kind and degree of sulphide mineralization.

From these considerations it is inferred that the sedimentary belt to the east of the Coast Range
granite in the Unuk River section merits investigation and may reward careful prospecting for ore-
bodies. The difficulties of transportation which have been encountered heretofore will be materially
decreased by the completion of the wagon-road to Sulphide creek. Prospectors will then be able to
devote a large part of their energy to the search for and development of metalliferous veins in the
region.

The Unuk river was visited by Geo. A. Clothier, former Resident Engineer of District No. 1,
in 1920. In the 1920 Minister of Mines’ Report will be found an account of his trip. The follow-
ing is Clothier’s report of the best means of access into the region :—

The Unuk river is reached from Ketchikan, Alaska, where all the coastwise boats, from Seattle
and Vancouver to Alaska ports, call each way. From Ketchikan there is gas-boat service to Bell Isle
hot springs at the mouth of Burroughs bay, with which arrangements can be made to be taken to
the mouth of the Unuk river at the head of the bay. All supplies, including a river-boat or small gas-
boat, can be procured at Ketchikan, for either has to be used from the mouth of the river. A river-boat
is built about 24 feet long, shovel-nosed at both ends and with a slightly curved bottom for handling
in swift water. It is fitted with oars, poles, and a long line for “lining” up the fast water. A
“kicker” can be used to good advantage as a help in fast water. There is no use in one man
attempting to go up the river alone; two at least and preferably three are better. The river is
navigable in this way for about 25 miles from the saltchuck or about a mile or two above the canyon.
From there is a good foot-trail to the upper end of the canyon over which all supplies must be packed
on men’s backs for about 4 miles. Here, if one is lucky enough to find an old boat, he can go on up
the river. by poling and lining, for another 12 miles to the South Fork, 14 miles to the mouth of
Sulphurets creek, also flowing into the Unuk from the south, and about 20 miles to the head of the
main river, though I believe it is navigable for only a short distance above Sulphurets creek. The

game is goat, bear, and birds. A great deal of trapping has been done in that section, but I have no

information as to the chances along that line now. ‘The best time to get in is early in the spring as

soon as the ice goes out, which is generally the latter part of April or the first of May. It is a
_dangerous trip at any time, but much worse during high-water time. if one wants to stand the
expense, I believe that there are men in Ketchikan who will take you up in a gas-boat.