The news and herald. (Winnsboro, S.C.) 1877-1900, 1879-12-13
SCI ENTIFIC,

The California Gravcls In an inter-
esting sketch of the California gravcls
by w. A. Goodyear, before the Califor-
MIA Academy Of Science, tie author
claims that the whole character Of the
gravels proved they were the work OF
running streams Of fresh. Tho bed
rock Of the western slcpc Of the Sierra
Nevada has never, he says, been snb. .cct-
ed to any considerable movements OF
elevation or depression. The seat OF
volcanic energy lay to the east of the
gravel region, which was overwhelmed
with debris, without much disturbance
of the bedrock. The general direction
of drainage, throughout the period of
accumulation of the aurifcrous gravcls,
must have been southwcstcrly. The
"Bluc Lead' theory was based on the
fact that sometimes the ancient streams
flowed for several miles south or south
east, that Is, nearly parallel with the
axis OF the mountain range. The
streams were, in all probability, subject
to greater variations in the quantity Of
water which they carried ut different
times than the streams of to-day. The
channels of some of the streams were
exCavated into the solid bedrock to
depths of from 100 TO 800 feet. The
process OF accumulation OF gravels must
have been very slow, occupying hum
dreds, and perhaps thousands, OF years.
Excavation occurred at ono place while
accumulation went on at another. Tho
streams flowed at first OH the almost
naked surface of the bed rock. When
channels had become filled to the level
Of the lowest portions OF the surround
Ing country, the stream would break
through or over them, leaving the old
f.h l,n
crooked, like the old, and would, in due
time, fill with debris and burst its
banks. This process went on, with
thousands of streams constituting the
drainage system on the mountains, un-
til all the lower dcprcssions were filled
with gravel, the lower knolls covered
with it, ana as its depths increased, it
crcpt up the sides OF the larger hills.
Tho Volcanic Period put an end to the
Gravel Period; yet the western slope OF
the Sierra Nevada was never flooded
with liquid fire, as the volcanic matcri-
ais spread over that region are fragment
tary, and have been transported by the
action of water. Tho whole country
over which the gravcls had accumulu-
ted were simply flooded by successive
flows of volcanic muuS and debris of ali
sorts. When the volcanoes died, the
modern streams began their work; but
the ancient gravels were buried to
depths ranging from 100 to 1000 feet
beneath volcanic detritus. Throughout
the basin. Of the middle lork or the
American River the depth of the VOL
canlc cnpDing ranged from 300 to SOC
feet, ana places can be found near the
crest of the range where the depth
reaches from $40 to 1000 Icct. The
higher ranges Of the bedrock hills
served to mark and determine the out
lines of the larger drainage basin Of the
new system, as they did OF the old.
The SUI face Of the country ut the close
OF the Volcanic Period was smoother
than Mt the CONNIE of the
Gravel epoch. Where The accl,mula-
tions OF these gravcls were great and
deep, aid where the volcanic Gaping
has been subsequently, removed, or was
never very thick Cor, as is probable Mt
some localities, never existed at alD,
there are found the great hydraulic
mines. Where the gravel was shallow,
but rich, and was covered by Il heavy
mass of volcanic materials which has
never since been removed, there arc the
"drift" or "tunnel diggings.'