Richmond dispatch. [volume] (Richmond, Va.) 1884-1903, 1899-11-05
JAMES RIVER ROCKS.
A GEOLOGICAL HISTORY or THE
BouLDERs IN THE STREAM.
SOMETHING ABOUT "POT-HOLES. "
Curious Effects Caused by Centuries
OF Rushing Water-The Old Course
of the stream, and How IL Has
Been Diverted.


Whoever has observed the superficial
appearance OF our granite-its some
tines sinuous or wayy texture-will
readily accept Sir Charles Lyeirs conjec-
ture as 10 its origin; that it IS a meta
morphlc rock, which has been formed
under the pressure probably Of the sea,
and subjected for untold ages to a feryld
heat OF its supporting mass. Whether
made UP Of the debris Of rocks once Or
ganic or inorganic. is certainly unknown;
but that Il may have been at some period
of geologic time in a plastic state is not
at all doubted by those who have made a
special study of It's phenomenal origin.
THE BEST OF ITS KIND.
The granite underlying Richmond and
its vicinity is acknowledged by civil en-
gineers and architects 10 b0 the best or
It's kind to be found anywhere outside OF
Virginia. 1t is made mp in the main ot
quartz. mica. and feldspar, and owes It's
hardness and color to a natural blendlh5
of these three constituents. our river
has had hard work eXcavating a passage
through it TO the sea, ana but LOT the
service rendered by the pot-holcs-those
tireless little workers-might nave been
many ages behindhand in its progress
thither. ,
The great rock-wall an upheayal Of
archaic time. which extends lensthwlse
from q point south of Petersburg TO an
other north of Fredericksburg was az
oue period as barrier on It's west
hampton side 10 the rushes or the old
river and on its eastern, or lower side
10 the waves OF the tertiary seas. That
this old river was IN existence IN
furassic age. and discharged It's waters
into the deep cups OF the granite beyond
the western base Of the barrier IS evil
denced by the presence OF coal heid7
there. bearing, according to the testi-
mony of Lyell and Rodgers the we'll
known fossils Of the Jura.
COURSE OF THE RIVER.
This phenomenal upheaval Of metamor-
phic rock appears in outcrop al higher
levels on the south than on the north
side of the river, as observed by me IN
the particular section overlooking the
falls. IL is there on Jhe right bank up
wards Of one hundred feet above tide
water. with a plane sioping TO the eas'
or northeast. Through this adamantine
barrier the old riyer-of greater age
above than below the foot Of the falls
has cut its way 10 the sea. first on the
Welding left shore, and subsequently on
tho right or Manchester, side. Belle
Isle was once "a part of the mainland as
shown by a similarity Of It's rock struc-
ture and superintendent c.ay5 ana
gravels. The Presence at this day or
enormous powders which clog the mar
row. shallow stream that divides it from
It's parent main OF the sOuthside is
a. nf fffr ri oh
servation. No such powders are to be
seen in the section Of the falls lying
between Belle isle and Richmond and
for an obvious reason. II once there,
which IS very likely, they have been
worn down. or ground to powder by
the ice. or broken up by the longer action'
and wider sweep Of the currents OF the
old river
The course of this old river before
Belle Isle had been detached from the
south main. and before it had cut cir
cuitous passage TO uoewater. was
straight on. and over the lofty upland In
rear OF the corporate limits OF Manches-
ter on the west. The Old shore-lne SUI
exists in testimony OF the old course OF
the river, and may be traced from the
SwansbOro' suburb up as far as the site
OF MannilSin.
THE WORK OF GLACIERS.
Bowlders OF huge slze--some weighing
hundreds of tons and all water or ice
worn. besides ailuvial clays and gravals,
are found al NELSON'S. near Fine Greek,
pOwhatan county. and near Bon AIR.
Chesterfield county. so group as 70 make
the conjecture reasonable that their pres
ence there is owing 90 the action OF the
glacier. Or. Henning of POwhatan in
forms me. through friend. that similar
powders are 10 be seen southeast Of Wes-
sons, IN line which marks distinctly the
extent and detection OF the old river from
its ultimate trend towards the sea. This