Custer weekly chronicle. [volume] (Custer City, S.D.) 1890-1931, 1913-11-29
0. S. GEOLOGICAL SURVEY
important Work in Geology in South Da.
kota-Investigation of Water
Resources Pushed.

Dakota is so bound up with the develop
ment of its natural resources that the
work in this state of the United States
geological survey is always of interest
Field work is being carried on this veal
by the survey in geology, investigation
of water resources and topographic maj
making.
The geologic branch of the survey il
making detailed study in pre-Cambriar
geology-that is, of the most ancient o.
the geologic formations-in the areai
known as the Deadwood, Rapid, Har
ney Peak and Hermosa quadrangles
The detailed areal studies are prosecut
ed by Sidney Paige, assisted by G, l.
Harrington and G. d. Thompson. The
results will be published, with complete
geologic, economic, and Topographic
maps, in geologic folios. The field work
on certain rock formations of these
areas, as we'll as of the Newell quad.
rangle, has already been completed by
N. Ii. Darton.
| BLACK HILLS ARE SCIENTISTS KEY
The Black Hills are of especial inter.
est because they furnish key to the
geology of the rest of the state and oi
considerable areas in surrounding states
They owe their existence to a gradual
upheaval which arched up the various
layers Of the earth's crust, carrying very
ancient and deeply buried rocks up
thousands of feet. In the ages that
have passed since the upheaval the
dome thus formed has been eaten into
by the forces of weathering and erosion
until the most ancient rocks known
the pre- Cambran granite and the schist
are now exposed at the surface in the
central part of the hills. Around these
rocks in consentric rings are the success
sivelv younger and higher formations.
These exposures afford abundant oppor-
tunity for study of rocks and records OF
ages gone by which could be reached in
other parts of the state only by sinking
shaft far into the earth, and even then
only few square feet of each stratum
would be accessible, whereas in the
Black Hills each stratum is laid bare
over many square miles.
GOLD, TIN, TUNGSTEN, ToURMALINE, ETC.
The pre-Cambrian and Lower Cam
| brian rocks at some time or other
l,either while they were being formed, or
during the time when they lay thou
sands of feet below the surface, or while
they were being upheayed, became
locally impregnated with millions OF
dollars worth of gold. Tungsten ore,
mica, tourmaline, and other minerals
are abundant in the pre-Cambrian rocks,
and tin, though not present in CONNER
cial quantities, is also found. The prin-
cipal ore body at the Homestake mine,
one of the largest in the world, has been
the scene Of very extensive operations.
The ore, however, is not very rich, much
of it being worth less than $5 ton. On
account of its large amount, however,
and the ease of separation of the gold,
it is worked with much profit.
OCEAN wAvE-MARKs MILLIONS OF YEARS OLD
Among the interesting things which
can now be seen in the Black Hills are
parts of the old wave-beaten surface of
the pre-Cambrian granite and schist,
that lay buried for period of perhaps
one hundred million years which elapsed
between the time when the sea began
to wash over and deposit sediment
upon it and the time when it was again
exposed to view. The younger and
higher layers of rocks which surround
this granitic core contain fossil shells,
ripple marks and certain features of bed
ding which show that during many
millions of years the region was inter-
mittently covered by the sea and eleva-
ted above sea level. The region has
now been land for very long time, and
during this time not only has the noun
famous mass been worn down almost to
its "roots" but other changes have; ;taken
place, as, for example, the dissolving of
parts of lime which had been deposited
in the sea, giving rise to such caves as
the famous Cave of Winds, which is now
q national monument.
ToPoGRA PHIC MAPPING IN PROGRESS
The topographic branch of the survey
is engaged in revising the mapping of
the Spear6sh and Sturgis l5-minute
qnadrangles, in Meade and Lawrence
counties. Each of these quadrangles
has an approximate area of 2l4 square
miles. This work is being done by
Topographer r. w. Berry and will in
clude the detailed surveys necessary to
prepare maps which will show all rivers,
towns, roads, and railroads, as we'll as
the surface relief of the country by
means of so foot contour lines. The
completed maps will be engraved on the
scale of mile to inch and will pro.
badly be ready for distribution about
two years after the completion of the
field work.
STUDYING THE VOLUME OF THE RIVERS
The water recources of South Dakota
are being investigated by the water
resources branch of the survey, in CO.
operation with other government bur-
eaus, with particular reference to the
flow of surface waters. In this connec.
ton gaging stations are maintained on
Grand River at Wakpala, White River
at Interior and Westover, Little White
River at Westover and Belle Fourche
River at Belle Fourche. These paginp
stations are maintained in cooperation
with the United States Indian office and
the reclamation service. At these sta.