The silver messenger. (Challis, Idaho) 1890-1912, 1899-12-05
Geology of Klondiike.

= by j. ID. Iyrrel, THROWS mnch
light on the interesting subject
of the geology of the Klondike,
as to where all this vast amount
of gold could come from; what
| was the character of the rocks
| that must have originally yielded
it, and how it was collected to-
gether in the extraordinary rich
, deposits found.
According to him, the rich
known region of the Klondike is
about 1000 square miles, bord-
cred on the west by the Yukon,
north by the Klondike river, and
south by the watershed of Stew
art and Indian rivers. The orig
inal rugged mountains hrve been
planned into gentle slopes by
glacial erosion, so the country,
is series of swelling hills and
deep valleys from 5000 to 1000
feet above sea level. The high
est point of this region is a ridge
about the center, called the
dome, from which the valleys
radiate toward the lower country
Rocks underlying this region
rarely outcrop, being overalid by
decomposed rock and luxurious
vegetation. The rocks under
lying the gold bearing'region'are
mica schists and quantities,
probably of Cambrian or Paleo.
zoic age, cut by large and small
veins of quartz and by bikes of
dark green basic rocks and ligh-
ter colored acid porphyries. The
sedlmentary rocks have been
metamorphism. The strata lie
In gentle folds, but little disturb
ed. The Klondike scists appear
appear to extend over a large
area both in Alaska and Canada.
But few traces of gold, however,
are found in these schists; the
gold is, however, concentrated
In the recent sands of rivers and
gravels of glacial moraines.
In the valley of Bonanza creek
is a deposit of well-rounded
gravel, 6 to 20 feet thick, lying
on bedrock, much decomposed:
pebbles are of white quartz and
schist of local origin. These
stratified sands contain bones of
mammoth, bison, musk OK, and
fragments of wood and peat; the
gravel is overlaid by peat and
spruce. Scattered through the
gravel, near bedrock, are mug
gets and particles of gold. The
gold extends down two feet into
bedrock. On Bonanza and Ell
Dorado creeks rich claims are
located In lateral glacial mora
Inc, the gold occurring at the
bottom of bed of coarse sand
apparently formed by glacial
action. The gold in large mug
gets, including much quartz, is
rough and little water worn.
The history of this is, that the
rock, with its included gold, de-
,ayed to considerable depth, and
his decayed material gradually
'rept down toward the valley
bottoms. From great ice sheets I
n the south. local glaciers scor- {
I'd off the decayed rock, which '
he streams from their feet sort. /
ID leaving the gold and gravel Y
rs a typical glacial wash in the I
bottom and on the lower bench
IS. The gold is thus derived
rom rock near at hand, out of
which it weathered, and from t
which by glacier and stream it S
vas carried down and concentra- c
ed i'd the valley bottoms. While L
ne gravels in the valley bot S
oms vary in thickness from 6 to L
. feet, gravel and clay on hill b
ldes may be 30 feet thick. p
luch of the ground is frozen in g
laces, even to a depth of 100 p
BET. Farther south along the ii
'alton trail the open country E
as free from frost in summer. n
5 shown by the holes of ground Ii
Iulrrn1c rrhA ao,.l1 - =. -