Evening star. [volume] (Washington, D.C.) 1854-1972, 1897-07-24

know that they are going to no new fields.
The country has been explored by expedi-
lions from the coast and geodetic survey
and geological survey, and books and
pamphlets to a large number have been
written about it by men who have made
careful inspections SO there is no lack of
information concerning the country ITSELF
the manner of reaching it, the climate
food supply, and obstacles which must be
overcome by the visitor
The Spur Expedition.
document was issued some weeks ago
by the geological survey for the Senate
containing the result of an exploration of
Alaska by party from the survey, under
the direction of ]. Edward Spur and two
geological assistants, last summer The
expedition was chiefly to visit the gold
and coal areas, in order to secure an in
tellisent conception of the resources of the
interior of Alaska. One purpose of the
journey was the investigation of the gold
resources of the Yukon. During the in
vestigation of the gold region all the
creeks and gulches which are known to be
actually productive of gold were visited.
The area reconnoitered comprised upward
of 10000 square miles. The report states
that. besides the gold found in the rocks
of the Yukon districts. there is reason to
expect paying quantities of other minerals.
The following information in regard TO
gold placers' is of especial interest:
Since the formation of the veins and
other deposits Of the rocks of the gold
bSil al elioI length OF time mas
elapsed. During that time the forces of
erosion have stripped off the everything
rocks and exposed the metalliferous veins
at the surface for long periods and the
rocks of the gold belt with the veins which
they include, have crumbled and been car
ried away by the streams, to be deposited
in widely different places as gravels or
sands or muds. AS gold is the heaviest of
all materials found in rock, ii is concen-
trated in detritus which has been worked
over by stream action; and the richness of
the placerS depends upon the available gold
supply, the amount of available detritus
and the character OF the streams which
carry the detritus away. In Alaska the
streams have been carrying away the gold
from the metalliferous belt for very long
period so that particles of the precious ore
are found in nearly all parts of the terri
tory. 1t is only in the immediate vicinity
of the gold-bearing belt, however, that the
particles of gold are large and plentiful
enough to repay working under present
conditions. Where a stream heads in a gold
belt the richest diggings are likely to be at
its extreme upper part
DigGings Now Being Worked.
I'm this upper part the current is so
swift that the lighter material and the
finer gold are carried away, leaving in
any places a rich deposit of coarse gold,
overlaid by coarse gravel, the pebbles be-
ing SO large as to hinder rapid transporta-
ton by water. 1t is under such conditions
that the Giggfngs which now being
worked are found. with some unimDortant
exceptions. The rich gulches of the Forty
Mile district and of the Birch Creek dis
trict, well other fields of less import
ance, all head in the gold-bearing forma-
ton.
"A short distance below the head of these
gulcheS the stream valley broadens and the
gravels contain finer gold more widely dis
tributed. Along certain parts of the stream
this finer gold is concentrated by favorable
currents, and is often profitably washed
this kind of deposit coming under the head
of bar diggings.' The gold in these more
extensive gravels Is often present in suffi-
Gent quantity to encourage the hope of ex-
work can be done more cheaply and with
suitable machinery. The extent of these
gravels, which are of possible value. is
very great. AS the field of observation is
extended farther and farther from the gold
bearing belt, the gold occurs in finer and
finer condition, until it is found in extreme
ly small flakes, so light that they can be
carried long distances by the current. 1t
may be stated, therefore, as general rule,
that the profitable gravels are found in the
vicinity of the gold-bearing rock.
''The gold-bearing belt forms q range Of
low mountains, and on the TANKS of these
mountains to the northeast and to the
southwest lie various younger rocks which
range in age from carboniferous to very re-
cent tertiary, and are made up mostly of
conglomerates, sand stones and shales with
some volcanic material. These rocks were
formed subsequent to the ore deposition
and therefore do not contain metalliferous
veins. These have been partly derived,
however, from detritus worn from the gold
bearing belt during the long period that II
has been exposed to erosion, and some of
them contain gold derived from the more
ancient rocks and concentrated In the same
way as is the gold In the present river
gravels."
Mr.. Spur says further in his report