Evening star., 1940-02-03
Of Stors, Men
And Atoms
Notebook Of Science Progress
In Field. Laboratory
And Study
BY Thomas r. Henri.

~ A'sS"s@o As' HC"Vs
Wild November winds OF 70,O00,0O or
100000 years ago howled through the
branches Of the dense forests that COW
cred northern North America-the for
ests in which modern life had Its begin
ning-and swept the dead leaves before
them into black pools and sluggish
streams.
Casts of these leaves were impressed in
the soft muds Ages passed. The forests
and pools disappeared. The animals and
birds of the great woodland vanished
from the earth. The muds, still bearing
the impress of the leaves, became buried
rock. The casts remained, like torn frag-
ments of scribbled note, to tell part of
the story of the lost millenniums to any
one who could find the key to the code.
Among these leaf casts, scattered from
Greenland to southwestern Tennessee,
were many which differed considerably in
details but with general resemblance
to the foliage of living poplars. Paleon-
tologists have been collecting them for
the past 10 years. They have attributed
them to all sorts of trees from poplars to
figs. Altogether these leaves, together
with peculiar forms of winged seeds and
fruit pods found in much the same local
tiles, have been used as the prototypes of
ia genuses and species recorded in mu-
scum collections.
On the lawn of the National Academy
of Sciences Building In Washington
grows an ornamental tree imported from
Japan-a katsura. It's leaves also are
blown by the November winds of the goth
century-some perhaps to find their way
to the muddy bottom of the nearby Po-
tomac, which some day will be rock where
their casts will puzzle geologists of far
distant future.
After 10 years of archaeological de-
tective work DR.. Roland w. Brown,
Smithsonian Institution paleobotanist,
has been able to bridge the millenniums
between this little tree in Washington
and the paleocene woodland.
Certain likenesses between the leaves
of the ancient forest already had been
noted. DR.. Brown started with the hy-
pothesis that if they really were katsura
leaves it should be possible to find in
the same localities casts of the peculiar
sickle-shaped and minute winged seeds
Of this tree. The proverbial hunt for a
needle in a haystack was simple COM
pared to the job of finding what were
little more than grains of sand in the
ocean of 100000 years.
In the first place, he explains, in re-
porting his investigation which involved
States, leaves are the only part of most
ancient vegetation at all likely to be pre-
served as fossils because of the winds
which deposit them in places where they
will make imprints in the mud. Wood
and fruits decay where they fall, leaving
no trace
The katsura seeds, however, were diff
ferent. Nature had formed them to be
distributed by the wind. 1t might be
expected that some of them would have
been deposited in the same sluggish
streams and pools as the leaves of the
same genus. Fossils of just such winged
seeds had been reported, but not in the
same places. They also had been attrib-
uted to all sorts of different species.
If leaves and seeds could always be
found in the same places, DR.. Brown be-
lieved, the identification Of both would
be established. In the course of his field
trips as Geological Survey geologist, he
always took the opportunity, whenever
he was in neighborhood where the leaf
fossils haa been reported, to seek for the
seed fossils.
He always found them in relative
abundance, he reports But he warns
paleontologists who may seek to follow IN
his footsteps, these tiny little fossils dis
tributed according to the whims of the
ancient winds, are far from easy to find
The quest might battle the genius of a
Sherlock Holmes and only long familiar
ity with the field would make it possible
At the same time he found closely asso-
ciated with the leaves and seeds fossil
imprints of remnants of the fruit pods OF
the ancient trees-or in those days the
katsuras may have been vines twining
around the trunks of the paleocene
trees-which are quite similar to those
of the survivors today.
There remained to be resolved the ex-
treme confusion of species and varieties
set up on the basis of the different
shapes and markings of the fossil leaves
DR.. Brown gathered large collection OF
the leaves of the imported tree on the
lawn of the National Academy Building
No two leaves of any tree are exactly
alike. He found a great variation In
these Goth century leaves and was able
to match nearly every fossil poplar leaf
in the collections of the United States
National Museum with some leaf actually
blown off single tree in one autumn.
AS a result of his investigation he has
reduced the lat species to 2, thrown new
light on the extensions of the ancient
woodland, and furnished another clue
as to its appearance in the days when
the first singing birds appeared in its
branches and tiny creatures who may
have been remote ancestors of man sour
ried up its tree trunks, scared out OF
their microscopic wits as fantastic mon
sters of the day, most of which have van
ished leaving no descendants, crashed
through the underground.