Evening star., 1934-08-21
SCIENTISTS STUDY
GROWING FALLS
v. M. |. Group Interested
in Waterfall Built Up
Through Ages.
BY THOMAS TX. HENRY,


The curious phenomenon of grow
Ing waterfalls near Lexington, Va, Is
being studied by scientists of the staff
Of the Virginia Military Institute
under a special financial grant from
the Virginia Academy of Sciences.
AT least these waterfalls in the
swift mountain streams did grow in
the past, but now they seem to be
reversing the process. The idea of
d waterfall actually building itself up
through the ages instead of wearing
itself down is in itself reversal Of
generally accepted geological behavior.
The interest of the Virginia SCI
entists was aroused by the deposits
around Lexington of porous, light
yellow rock known as travertine, ac-
cording to a report to Science, the
official organ of the American Asso-
citation for the Advancement of
Science, by Edward Steidtman of the
v. w. I. faculty. They set out to find
where the travertine came from.
discover CURIOUS MOSS.
They found a curious moss known
as philonetls calcaria which forms
under the swift running water on the
edge and face of waterfall. It
seems to thrive best In foamy water.
In such an environment 1t grows quite
rapidly with the outer growth grad
ually smothering the growth under
meath so that 1t dies. Normally the
dead layers Of moss clinging to the
face of the rock, having lost the liv-
ing tenacity with which they cling to
the surface, would soon be forced loose
by the swift water.
In this case, however, 1t was found
that the bases are reinforced by thin
sheaths Of crystalline calcite which is
deposited by the water itself. Thus
they are turned to q porous stone.
Then, as the moss grows, the process
repeats itself, leading to rocky ex-
tensions, both vertically and down
stream, Of the edge of the cliff over
which the water falls.
Falls Raised Is Feet.
The v. NJ I. investigators found
cases where falls had been raised 25
feet above the original bedrock and
pushed more than 100 feet down
stream. The living moss, they found,
gathered no calcite, but it gathers on
dead tissue In tiny, very fine grained
nodules. Considerable beds of traver-
tine formed in this way were found,
sometimes with imprints of leaves,
tree trunks and other plant struc-
lures.
The process must have been very
slow, requiring years for a perceptible
growth Of the waterfall. These cas-
cade deposits, Steidtman points out,
are distinctly stratified, with porous
deposits OF travertine l or 2 inches
thick alternating with thinner, more
compact deposits. This they interpret
as seasonal effect. The former rep
resented the lush growth of the moss
In Summer and the latter It's highly
compact, matted condition in Winter.
The grains making up the Winter de-
posits are coarser and the deposits
contain more insoluble matter so that
they form q denser rock formation.
Makes No Attempt ut Date.
This seasonal stratification, varying
In depth, may, in case it is possible
to date the deposits, serve as an index
to the weather of the past although
probably moss growing in water would
not respond so delicately to climatic
variations as most other growing
things. In his communication to
Science Mr.. Steidtman makes no at
tempt to date the time when the
waterfalls were In their growth period.
Now, he finds, the reverse has
started. The moss which changes to
stone has been reduced to mere
patches so that the upbuilding process
Is not rapid enough to Offset the nor
NAL wearing down of the swift waters.
Since the erosion era has set in chan
nels have been lowered from 10 to Is
feet and the falls have receded along
narrow channels as much as 100 feet.
Presumably, In short time, geologi-
cally speaking, the evidence of the
building process will have been worn
away.
Reason for Reversal Unknown.
The reason for the reversal is un-
known. Presumably, there has been
some change in the temperature or
purity OF the water which makes it a
less favorable environment for the
foam-lovlng moss. Otherwise the
building-up process might have con-
tlnued Indefinitely. 1t Is possible that
waterfall growth" is a unique process