Idaho County free press. [volume] (Grangeville, Idaho Territory) 1886-current, 1900-10-05

reached a somewhat lower eleva-
ton. but none of them reached so
low an altitude as the main Salmon
river, which in this part Of it's
course has an elevation of less than
1000 feet. From the east and
west divide between the Salmon
and the Clearwater, local glaciers
flowed south into the gorge of the
Salmon, but none appear to have
reached that river. From this
same divide glaciers flowed north
to the south fork Of the Clearwater.
The broad valleys Of both the
south and middle forks of the
Clearwater were covered by valley
glaciers, j. g. the local glaciers that
originated in the Bitter Root
range and the higher ranges that
form the inns of these basins
united to form u continent ice
sheet in each valley. The ice
covered all the lower hills in the
central parts of each drainage
basin and flowed westward up and
aver these hills, and finally mar
rowed into the deep canons which
form the south and middle forks at
and below $500 feet elevation.
The great ice sheet which at one
time covered British Columbia
east of the Cascade range and
which had u southwark flow dur
ing the time of deepest ice, did not
reach so Tar south as the Clear
water valley. The valley ice
sheets OF the south and middle forks
of the Clearwater closely cores
pond to what Russell has termed
the Piedmont type of glaciers.
The signs of glaciation in all the
region in question are distinct and
unmistakable. Morainal ridges
and terraces are common in the
higher valleys, but in general the
ice seems to have retreated at so
uniform a rate as to leave moral
nal matter in the form of diffused
sheet. There are numerous lakes
held in by morainal dams, as the
lower Payette lake and Trout lake
on Lake creek, a few miles south
east of Buffalo Hump. Only in a
few regions do the rocks withstand
weathcring SO as to preserve the
glacial scratches. At Buffalo
Hump the GRANTEES, schists and
quantities. equal or surpass the
best Maine and New Hampshire
granite in capacity to withstand
the elements, and the rock is
beautifully smoothed and scored
to within about thirty feet below
the summit of the Hump. The
glaciated stones are so smooth and
rounded at the angles that they
have often been mistaken for
water rolled stones, distinct
scratches being rare. In the
regions where the GRANTEES and
schists weather readily, the
matter consists of
smoothed stones of quartzite or
other resistant rocks, scattered
through angular sand and gravel
resulting from the disintegration
granite and schists. In many
cases the glaciated stones are re-
markably round and smooth
almost to the tops of the ridges
from which the ice flowed in oppo-
site directions, as ON Buffalo Hump
and on the much dissected ridge
Boise basin from the val
ley of the south fork of the Pay
cite. Much, perhaps most of the
morainal matter was sub-glacial,
which accoun ts for the great
attrition it received.
The water-transported deposits
Of the glaciers of this region were
were mostly "overwash,' i. e..
were sediments poured out Of ice
channels into open ground beyond
the front of the ice. These are
plain-like, as at War
rem meadows; at other times they
take the form of terraces in the
narrow valleys. The overwashed
gravels have been often regarded
as lake beds, especially when they
into bIoad plains. Not
seldom sediments were deposited
in the beds of streams and lakes
between the margin Of the ice and
adjacent hills.
A short distance south of Elk
City is a series Of glacial gravels
deserving special study. A gravel
plain one-eighth Of a mile to about
a fourth of mile in breadth, and
eighty feet deep, leaves the valley
of Red Horse river, and extends 7
miles westward, first going oblique-
" over hills more than 100 feet
high; then for two miles is on the
top of the hills Immediately adioin-
ing the American river on the
south; then crosses that stream
ascends hill; then
crosses the valley of Elk creek
nearly at right angles and ascends
another hill to Buffalo Hill placer.
The American Hill placer is part
Of this gravel system. l did not
follow the course of this interest
ng gravel system east or west of
he points named, but it probably
,an be traced for miles in both
The direction of
transportation was westward.
Above the point where this gravel