Evening star., 1932-08-02
NORTH AMERICA
FACES NEW FLOOD
Scientist Holds Inundation
of Continent for 18th
Time Is Beginning.
BY THOMAS r. HENRY.

H.
North America has had at least II
great floods and now is at the beginning
of another.
Such is the conclusion of DR.. Charles
Schuchert, member of the Committee
on Oceanography of the National Re-
comprehensive survey OF the present
scientific knowledge of the oceans just
issued by the council.
There is no cause, however, for i'm
mediate alarm. These floods have been
spread over approximately 500,000,000
years and it will be long time before
the one on the way reaches threatening
proportions.
The oceans food each continent in
definite and recurring patterns, Dr.
Schuchert says. One of the cycles be-
gins. he points out with a gradual
transgression by the ocean which grad
ually grows larger until the waters may
cover a large part of the continental
area. Then there is a gradual read
jastment of the land surface, mighty
moEQtains are raised and, eventually,
the flood retreats more or less COM
pletely of the continent and much
more suddenly than it came.
Beginning New Cycle.
The largest of the North American
inundations, he points out, covered ap-
proximately 4,675,0oo square miles, or
more than 81 per cent Of the entire
continental area. The smallest, and
geologically one of the most recent,
covered only 236,OOO square miles.
To-day" he says, I'VE are at the be-
ginning of a new cycle when the conti-
nents are largest. highest and scenical-
ly grandest. The oceans, however,
have begun another invasion upon
North America, as seen in the st. Law
renee embayment and most widely IN
Hudson Bay"
There has been an actual increase
with time of the amount of water in
the oceans he points out. These
Oceans, he holds, have been added to
the surface of the earth through geo.
logical time by the medium Of volcanic
acsiGn and hot springs. Originally, he
says, most of the oceanic water was
dissolved deep in the earth and had to
come out in the form of steam. Most
Of this was accomplished very early,
since among the earliest rocks known
are those laid down by water. There
fore, oceans existed at the beginning OF
the known geological record. From S
to 25 per cent Of all the water on earth
has been added since life began to be
abundant.
Ocean Floor Raised.
But. Dr. Schucher5 holds, a much
more notable factor in the recurring
floods is the raising of the ocean levels
b. drainage OF waste material from the
land into the seas.
1--WE are living" he says, 'in the
early part of the first third of new
cycle of geologic processes. We know
that in the last third Of a period the
lands begin to rise and that they con-
tinus highest in the first third of each
period. and are most often reduced to
their lowest elevation during the latter
part Of the middle third Of each cycle.
whsn the floods are the greatest"
Thus. he points out, the present must
be ore of those eraS when the ocean
floors are being built up at the greatest
speed. slowly pushing the waters over
the continents.
A third reason for the cyclic foods
he points out in the National Research
Council report, is the rising of volcanoes
from the sea bottoms thus displacing
enormous amounts Of water. These
volcanic grDwths, he says, probably rise
fairly rapidly to above sea level-in less
than half the length of a geologic
period. Once raised they are practically
eternal.
Sea Level Changes.
The fourth factor he advances Is that
of changing sea level The idea of a
constant sea level, he points out, no
longer can be maintained since it Is
disturbed by various factors in different
places.
THE causes for such long persisting
changes" he says, "are not yet known.