The Indianapolis journal. [volume] (Indianapolis [Ind.]) 1867-1904, 1898-05-01
UNDERGROUND STREAMS.
Thousands of Miles of S-ubterranean
Rivers in Kentucky.

J. r.. Proctor. in the Century.
Passing southwark through Kentucky on
the Louisville & Nashville Railway. the
observant traveller will notice that about
forty miles from Louisville the road climbs
Muldrow's hill. which is the northern es-
carpment of an elevated limestone plateau
road traverses this plateau for about one
hundred miles. and descends a southern
eScaTpment into the basin of central Ten
nessee. In this distance only three streams
are ~crosSed-Nolin Green and Barren
rivers; and between these rivers the entire
surface drainage passes away through sub
terranean channels, giving rise to a curious
sink hole' topography which is peculiar to
this region. These circular and oval-shaped
depressions are so numerous that in places
the rims almost touch one another. and one
can sometimes count several hundred to the
square mile. Through vents at the bottom
of these sinks the surface water passes
downward into cavernS and underground
streams, emptying into the a~bove-named
rivers through arched ways near water
level, and in places beneath the surface
of the rivers.
The surface rock of this plateau is the
subcarbonlferouS limestone, which is here
several hundred feet thick, a massive, re-
markedly homogeneous rock. with no inter
vening strata of shale or sandstone-condi-
lions most favorable for the formation of
caverns, consequently this region contains
more and larger caves, in a given area, than
any other region in the world. In Edmon-
son county,, where the celebrated Mammoth
cave is located. it is claimed that there are
as many as five hundred known caverns.
"A IdHS6 Oh Nils OF UNIFORM nelgnt, run
ming parallel with the railway and several
miles distant, will be observed to the north.
On nearer inspection this will be seen to be
a level plateau rising out of the limestone
plain, and held up by a Gaping of massive
sandstone. 1t is beneath the protection of
this sandstone-capped plateau that the
through this plateau to a depth of about 800
feet, and. as the sandstone cap is about
OF massive limestone exposed above the
drainage level. AS some of the domes and
upper avenues. Of the caves extend up to
the base of the sandstone and some down to
the drainage level, we thus have 250 feet
as. the present limit of the vertical extension
of these caves. The evidence is conclusive
that these caves have been cut down to
correspond with the deepening of the chan
mel cut by Green river. In the region i'm
mediately along the line of the railway,
Where the sandstone Gaping and the upper
limestone have been removed by erosion,
the caVernS have less vertical extension,
and correspond to the lower avenues of the
Mammoth and other caves to the north.
Doubtless large caVerns, corresponding to
those now remaining beneath the sandstone
plateau, existed here before the upper MEM
Der of the limestone was eroded from this
area.
There is no means of estimating the ex-
tent of the cavernS and subterranean
streams il this region. Every one of the
innumerable depresSions or SinkholeS-save
where the vents have been closed, thus
forming ponds-conlmunicates with an UNI
foreground channel or cave, and the aggre-
gate length of such channels has been esti-
AhdlGQ at MANY -lilCuSduCS VI IlllSS. NOT
can we form any estimate of the number
and extent of large caverns yet undiscov-
cred. But for the erosion caused by a small
stream cutting through the roof of Mann
moth cave the present entrance would not
have been broken open, and this, the great
est Of caves, might nave remained unknown.
Several other of the largest and most beau
tiful caves in this region have been found
by accident. Hidden grandeurs doubtless
yet remain entombed beneath the extensive
uplands reaching out on both sides of Green
river.
In crossing the southern upland we come
upon oval-shaped limestone valleys, sur
rounded on all sides by a sandstone rim,
with no outlet save through vents in the
bottom. These valleys are sometimes hun
dreds of acres in extent, and are probably
formed by the falling in of extensive cav
erns, the debris. disintegrated by the ele-
ments. being carried away through the sub
terranean channels. The fact that existing
caves under the hills surrounding these
valleys have been found through entrances
in the sides of some of the valleys is an in.
dication that this may have been the con-
dition.