Evening star., 1937-10-23
STARS, MEN AND ATOMS
Notebook of Science Progress in Field,
Laboratory and Study.
BY THOMAS r. HENRY.

Approximately SOC, 900 900 years ago
the curtain rises on the drama of life
on earth With fantastic array of actors
on the stage and speaking their lines
Behind the curtains, up to now, has
been silence and darkness.
These earliest forms of life. which
appear in the so-called Cambrian Age OF
geological history, constituted queer
assortment. The dominant types were
creatures not unlike the present-day
crabs. These trilobites lived in the shall
low waters close to the shores OF ancient
seas For the most part, they probably
crawled on the bottom. Their forms
were left imprinted in the rocks. which,
in the course of millions of years, were
formed from the bottom mud.
Consequently, they are fairly well
known. The United States National
Museum has probably the worlds larg-
est collection of them. 1t is possible even
to tell something Of their ways OF lie.
Now, relatively speaking, a triloblte is
almost man. He is far more than half
way between a man and microbe, or,
for that after, between man and
sponge. The ancient crab had about the
same sort of organization as a human
being or a dinosaur. Presumably, the
very earliest forms OF life were single
celled organisms The trilobites were
multi billion n-celled organisms. There
must have been gap between them and
the beginning much vaSter than the
known gap between them and the
present.
II is known also that the half billion
wears since the Csmbrian comprises less
than a fourth of the life span of the
earth. as determined by the latest ura-
mum count calculations. The globe had
had plenty of time to solidify and cool.
In fact, by the time of the trilobites, 1t
was a rather pleasant place in which
TO live. There was an eQuable climate
nearly everywhere. The land surface
was rather monotonously level, but one
hardly can attribute to trilobites any
very finely developed esthetic sense.
So far as is known the dry land was
completely barren. Probably not even
plants had started their migration out
of the seas.
There must have been at least a bill
lion wears preceding the trilobiteS in
which life was in existence and evolving
from the single cell to higher organisms.
But for those occupying the box seats
of the present there has been no glimpse
behind the curtain-or only such rare
elimpses as were afforded by question
able mike trails in the rocks and
deposits of a form of iron supposedly
secreted by certain marine plants.
The first real break beyond the Cam
brian into the darkness which stretches
to the beginning of things appears to
have come with the recently reported
finds in South Australia by Sir T. w.
Edgeworth-Dav and r. j. Tillyard. AS
long ago as 1922 they reported finding
prominent worm trails in pre- -Cambrian
rocks near the city of Adelaide. The
findings were so doubtful. however that
even biologists who inspected them per-
sonally had grave doubts. Ripples of
water might have made trails in the
mud very like squirmings of worms.
The two Australian paleontologists
continued their work and now report
definite findings of three distinct "hori-
IONS OF life" below the Cambrian. They
seem to have extended the story of life
a hundred million years or so further
toward the beginning.
They have scared out some weird
creatures from this backstage region.