Evening star., 1931-12-11
GREAT ICE SHEETS
DIARIES STUDIED
Records Left by Retreating
Glaciers Tell Story of.Life
Of Early Man.
BY THOMAS r. HENRY.

The great ice sheets which covered
the Northern Hemisphere in the dis
tant past kept their own intimate
diaries.
These records, in which biologists
can read about the hard Winters and
hot Summers before man appeared on
earth, and even of some Of the vicissi-
tudes Of early man himself, are de-
scribsd in the annual report Of the
Smithsonian Institution issued this
week.
A retreating glacier, 1t is explained
by Chester A. Reeds, noted American
geolOgist tends to melt in Summer, the
amount of melting depending on the
heat and length OF the season. Because
of this melting streams flow off from
the edge Of the ice-sheeJ and flow into
lakes to the southWard. These streams
carry with them a good deal Of dirt,
solid particles from the glacier itself or
picked up from the channels through
which they move. once IN the lake the
particles sink TO the bottom, forming
g thin layer over the beG.
Layers Tell Story.
Winter comes and the glaciers freeze
UP tight The surface water Of the
lake cOOlS and sinks to the bottom, car
rying with it the lighter particles which
it has picked up during the Summer.
These form deposit covering thai
brought in by the glacial streams and
OF a different color. These two diStin-
guishable layers will be deposited year
after year, until the glacier has re-
treated out of that neighborhood
Naturally, Reed points out, the hot
ter the Summer the more melting and
the thicker the glacial stream deposit.
Many of these old lake beds in the rear
of the retreating glaciers IN Europe and
North America have been found. BY
exact measurement of the thickness OF
the "varves," as the deposits are called,
ReologistS are able to reconstruct a cal
endar of the distant past.
A study of "Varves" at HeVerstraw,
N Y, and New Haven, Conn, left in
'the wake Of the last glaciation, Reeds
says, reveals periods Of hot and cold
years which seem to follow periods Of
variation found by astronomers in the
heat radiation Of the sun. The varia-
tions, he says, were governed by
changes in the weather and in solar
radiation extending over a period Of
more than seven and One-third centu-
Ties. The discovery of this relationship
in the distant past is considered Of
especial Importance because Of recent
efforts to correlate solar radiation Yaria-
tions with weather, which may eventu-
ally form basis for long-range weather
torecaSting
Light Thrown on Man.
The study of these "varves" in Eu-
rope also throws considerable light on
the age Of the human race in that
continent where many scholars believe
1t originated, according to Rev. DR..
Stephen RicharZ, priest-anthropolog
of the Catholic University Of America,
in the same report.
AT least a minimum age can be as
signed to mankind" he asserts. This
is approximately 10000 years. He cal
Culates, on the basis of ancient lake
deposit layers the time which was re-
ouired for the last great glacier which
covered Central Europe to have re-
treated northWard into the Arctic. 1t
us known that human beings were in
Central Europe In the period just before
the advance Of this glacier. when the
climate was mild, ana that they re-
manned at the edge of the ice, in South
ern France and Spain, during the
glacial period. Thus their presence on
the continent covers at least the entire
stretch Of this glacial period.
Facts which are obvious and uni
versally accepted by all geologists," ,"
says Father RicharZ, warrant the
conclusion that man was undoubtedly
in Europe 10000 years ago. OF this
number Of milleniums, the first half
Is determined by exact methods, The
second held partly on an estimate Of
the recession of the ice and partly
on a very conservative estimate cf the
time required for the advance Of the
ice front from Northern to Central
Europe.
Theology Not Involved.
1T seems impossible that the figure
Of 10000 years will ever turn out to
be too high. 1t is impossible to recon-
Gle the well known facts Of human
antiquity with such figures as 5000 to
5000 years, as was assumed by the
older Biblical exegesis. No theological
problem is involved. Theologians, even
the most conservative, acknowledge full
liberty to deviate from the figures of
the older eXegesiS and declare that the
problem Of the age of mankind, like
that Of the age Of the earth and Of
the universe, is one which has to be
solved by secular science"
Father Richarz, however, does not
subscribe to the theory that man orig
mated in Europe, hence the exact
'varve' chronology which has been
worked out for that continent gives
q clue to only part Of the actual