The Somerset reporter. [volume] (Skowhegan, Me.) 1868-1909, 1892-03-24
The Crea Sand Dunes.

1
estimates the sand dunes Of Hatteras and
lienlopen are in some cases upward Of
seventy feet In height and moving al lie asi
fifty feet year. Swamps have thus been
filled, forests and houses buried and ii il
stated that but few years can elapse be.
fore the entire island lying north Of Cape
Hat'eras will be rendered unlDhabitaDle.
Inc sand dunes on the coast Of Prussia
commenced not over 8 century ago and
already fields and villages have been burr
ed and valuable forests laid waste by
them. tall pine forest covering many
hundred acres was destroyed during he
brief period intervening between l-04
aud 1927. Lotus, writing Of Niliyga, an
old Arab town q few miles eat II I {
ruins Of Babylon, ssys that In l'is the
sand began to accumulate about il, and il
Six years the desert within radius Of siX
miles WAS covered with little undulating
dunes, while the ruins Of the city were 80
buried that II IL now impossible 70 trace
their original form and extent. still
more striking illustration Of the rapidly
OF these sand accommodations Is Il red by
the same authority IN describing the
burial customs Of some Of these ancient
people, 1t being stated that the earthern
ccins were merely stacked in layers one
On top of another and left thus to be GOV
cred by the fine sand -ifted over them by
the winds Of the desert. From Nineveh,
founded some twenty centuries before
Christ and destroyed 400 years later, be
came SO, covered by drifted sands that a. the
time Of the Greek /enophon (about 400 B.
G. the verv site OF the once famous city
was unknown.
1t is not possible always to trace the
drifted sands to their various sources.
Dunes along the seacoasts are in nearly II
not quite all cases composed Of materials
thrown up by the waves Of the beaches
This is the case with those Of Hatterss,
Cape Cod, GlsscOny Algeria and SCnleswig
Holstein. But the origin Of the large in
land dunes like those Of Nevada is not SO
clear. 1t has been suggested that these
may have been formed of beach sand
driven in by the prevailing westerly winds
from the Pacific coast. This is, however,
matter of very grave doubt, and it seems
more probable, as stated by Mr.. | Z. Rus
sell, that they are derived from the disln-
tegratiug granite of the Sierrss They
certainly have travelled far snd are not q
product of disntegrstion of rocks in the
immediate vicinity.
The agency of the wind does not end
with the work Of Transporting the sand
and dust. Particles Of sand drifting
slong before the wind become tn. mselves
sgen's Of embrasion, fling away every
hard object with which they come in con
tact. As matter of course this phenom-
enon is most sirikingly active in the aid
regions, though the results, when looked
for, are by no means wanting in the hu-
mid east. 1t is thought by Prof Egleston
that the inscriptions on many Of the
tombstones in the older churchyards Of
New York city have become illegible by
the wearing action of the dust and ssud
blown agsinst them. There is to be seen
in the National Museum at Washington a
large sheet of plate glass, once window
In lighthouse on Cape Cod. During 8
severe storm of not above forty eight
hours duration this became on its expos
ed surface SO ground from the impact of
grains Of sand blown against as to be no
longer transparent and to necessitste its
removal.
Apply now this agency to a geological
field in a dry region. The wind sweeping
across country bare of verdure and
parched by drought catches up particles
OF dust and sand and drives them violent
along more quietly close to the surface
where they are at first scarcely noticeable.
The impact of single one of these NOV
ing grains on any object with which it
may come in contact is in6nitesimsl, but
the impact of millions acting through
long periods of time produces striking
results. Urged by the winds the grains
go sweeping on, undermining cliffs, scour-
in tai
the loose boulders, and smoothing out al
inequalities. Naturally the abraiding &C
ton on exposed blocks of stone j. mos
rapid near the ground, as here he hyin.
sand grains are the thiCkest. First th
sharp angles and corners are worn away
and the masses gradually become pear
shaped, standing on their smaller ends
Finally the base becomes too small fol
support, the stone topples over, and TIT
process begins anew without moments
| intermission and continues until the en-
tire mass dissppears-becomes itself con
verted into loose sand drifted by tn,
wind and an agent for destruction. W
P. Blake was the first to call public atten
tion to this phenomena, having observed
1t while in the Pass of San Bernardino,
Cal, In 1853. G. X. Gilbert has also pub
lished interesting facts upon the subject
as noted by himself while geologist of
the Wheeler expedition west of the Tooth
meridian in ls7l.72. In acting on the
hard rocks the sand cuts so slowly as at
times to produce only grooves or fantss-
tically carved surfaces, often with very
high polish. The geologists of the For
tieth Parallel Survey in 1867 described
like interesting phenomena as observed
on the western faces of conglomerste
powders exposed to the sand blast of the
desert regions Of Nevada. Engineering
Magazine.