Evening star., 1938-12-03
Of Stors, Men !,
And Atoms i
Notebook Of Science Progress
In Field, Laboratory
And Study
BIZ Thomas r. Henry.

By Thomas r. Henry.
Cryptic records Of lost million y....s
Of life's history now are being decoded
by Smithsonian Institution paleontolo-
gists.
DR.. G. Lewis Gain, Smithsonian
paleontologist, has just returned from
a site first opened last year in Western
Utah, from whose torn and battered
rocks he recovered teeth and bone frag-
ments of -blooded creatures who
preceded the present mammals on earth
and may have been indirectly ancestral
to them.
The rocks were laid down in that
crucial period between the end Of the
Cretacious era and the extinction of the
great reptiles about 100000 years ago,
and the dawn Of the Eocene, approx
mately 100000 years ago when, as II
in a great explosion Of new life, the
modern types Of birds, mammals, fishes
and Towering plants first appeared. 1t
was time when the lowly mammals,
freed from the competition of the dino
saurs, were becoming earth's dominant
creatures.
Far back in the Cretaceous there were
crude mammals opd mo -, ~ a ll;La VAN
tiles, weak, clumsy. creatures, who cut
very little figure in the turbulent life of
the time. Then the stage was cleared
for them and for the budding of that
great April of time, the Dawn Age The
approximately 100000 years between
the end Of the Cretaceous and the begin
ming of the Eocene is now called the
Paleocene
The classic locality has been the San
Juan Basin in New Mexico In the San
Juan rocks, piled on top of each other,
are two mammal horizons" The first
is the so-called "Puerco" horizon in
whose rocks are found the scattered and
broken fossil bones of varieties of man.
mails utterly unlike anything now known
WA S~A eAAs SAoASS SAdAAoy SACdtulC UOtll
flesh and grass eaters. Just above the
Puerco is the so-called Torrejon horizon,
In which are found the bones of much
the same types of creatures, but showing
evidence of considerable evolutionary ad-
vancement Considering the slowness
with which evolution works, there must
have been a great time interval between
the two. The great deposit of Paleocene
fossils opened up by the Smithsonian
Institution few years ago in the Crazy
Mountain region of Montana may fall
partly into this gap, but most of the
forms are such as can be matched In the
Torrejon horizon.
The rocks with which Dr. Gain worked
this summer seem to fall squarely into
the gap. The mammals are further ad-
vanced than those of the Puerco and not
so far advanced as those Of the Torrejon.
They are represented only by fragments
which are difdcult to interpret and these
teeth and broken bits Of bone will require
much further study. There is one flesh
eating animal, about the size of a collie
dog. Another belongs to the race of
tologists to be connecting link between
the hoofed and clawed mammals, al
though not directly ancestral to either.
There are also fragmentary remains of
insectivores, race best represented at
present by the shrews, who are believed
to have remained closest to the original
stock from which all mammals origi-
mated.
All these Paleocene mammals, as de-
Scribed by DR.. Gain, were an awkward,
stupid lot. Their brains were small,
compared with those of even the
"dumbest" mammals of today-hardly
an improvement over the brains of the
cold-blooded creatures who had gone
before them. But the new race had
capacities for development and adjust
ment which their predecessors appar-
emily had lacked.
All these creatures were extinct before
the beginning of the Eocene. There is
nothing alive today, says DR.. Gain,
which even remotely looks like them.
The ancestors of the present-day NAM
mails were doubtless alive somewhere in
the world at the time and were at least
distant relatives of some of those whose
bones are found in the Utah formation.
These themselves, however, represented
divergent lines ill-ftted to survive.
They might be looked upon as discarded
experiments of nature in devising types
fitted for life in the modern world.
The Paleocene formation explored by
DR.. Gain, lies directly on top of Creta-
ceous rocks in which was found last year
the bones of great dinosaur, appar-
emily one of the last of the great reptile
race. There is no discernable boundary
between the two rock strata, and the
great sweep of time which must have
intervened can be deduced only from
the difference in the fossils.
DR.. Gain has named the new rock
page OF earth's history the Dragon hori-
zon," after the Utah canyon in whose
walls the bones are found 1t was first
found three years ago by Drs. E. S.
Spieker and J. B. Reeside, jr., of the
United States Geological Survey and the
first systematic exploration was carried
on in the summer of 1897.
These Endure
I have known sorrow; have known
laughter,
Y7~l~ ~1~ L.