Evening star. [volume] (Washington, D.C.) 1854-1972, 1929-10-23
TREE CALENDAR
TO GIVE SECRETS
Early American Ruins to Be
Studied With Unique
Rosetta Stone"

Dating the occupancy period of tn,
famous Pueblo Bonito, in Chaco Can
yon, New Mexico, giant communal
dwelling which has been called Amer
ica's first apartment house" and o
some 40 other major pre-C Columbian
ruins of the American Southwest, Is II
immediate prospect, according to al
announcement today by DR.. Gilber
Grosvenor, president of the Nationa
Geographic Society.
Study and codification of about 5000
tree sections, including a series of cross
sections located this Summer after years
Of search, is being concluded by Neil M
Judd, leader of the National Geographic
Society'S expeditions which revealed
Pueblo Bonito. and by DR.. A. E. Doug
lass, leader of the timber and wooden
beam research parties which are about
to yield the answer to Americas fore
most archaeological problem.
scientific Detective Story"
These scientists and their aids, the
National Geographic Society explains
are about to write the final answer to a
scientific detective story that has
progressed through chapter after chap
ter until this Summers work eliminated
in finding the missing tree ring links
that spell the solution.
to date the period when the complex
and highly developed civilization Of
Chaco Canyon reached its elimination
In the Beautiful Village pueblo Bon
ito), a communal dwelling of some $500
people, centuries before the white man
set foot on American soil. There this
aboriginal people, with no apparent
communication with the Egyptians,
Babylonians or ASSyrians, constructed
their masonry residence, equipped 1T
with household utensils, furnished cere-
monial chambers and wrought intricate
jewelry of marvellous beauty.
Many Art Treasures.
These mementoes of a civilization
which rivaled those of the ancient Old
World cultures. of which the BonitanS
apparently knew nothing, have already
been brought to Washington from year
to year, and have been viewed by thou
sands and pictured in publications the
world over.
But always there was the perplexing
question about Pueblo Bonito, as about
the other pre- Columbian ruins, How
old are they?"
Archaeology, botany, astronomy, mi
photography and plain "sleuthing"
were brought to play to solve this
scientific mystery. The trail led along
the tree rings patiently collected from
sections cut in various parts OF the
southwest, to be compared with SINH
lar rings found In the ancient wooden
beams of Pueblo Bonito itself.
How Calendar Worked Out.
Years of painstaking research were
based on the commonly known fact
that tree growth deposits ring for
each year of the trees life, and under
a microscope each years ring shows
individual characteristics. Lean years
consequent tree nourishment, are regis
tered indelibly and Enthusiastically.
Therefore it follows that trees which
have grown in the same region and
thus have been subjected to the same
cycle Of dry, normal or moist years
will show the same characteristics, and
their timbers can be identified by COM
parison.
The life of single tree in New Mex
leo will not span many centuries. But
an old tree and young tree, growing
side by side, will register the same sea-
son records. Thus the young tree can
be dated and will carry on the record
for years after the older tree has fallen
or has been cut for timber.
Hence the problem was to take the
beams of Pueblo Bonitc and those OF
OGner RUNS ana Dy matching The OVER"
tapping sections of one series Nth an
other until the record was linked Up
with sections of living trees rec IN
struct the tree-ring calendar.
Solution Near, But Baffiin'..
When this seasons work started the
scientists were so near a solution that
the lapse in their records was all the
more bafling. They had worked back
a chronology after years of patient
study of old timbers and sections of liv-
ing trees that gave them a calendar to
1860 AID. They had established an
other chronology covering pre-Colum-
bian period of 586 years.
All so far proven was that Pueblo
Bonito dated some time before 1860.
To get exact dates it was necessary to
dovetail the two chronologies. Is there
O gap between? Or do they overlap?
Telegraphic adviceS to DR.. Grosvenor
give assurance that the timber sections
collected this Summer are adequate to
link the two calendars, and thus solve
a major problem affecting all the i'm
portant Columbian ruins Of the
Southwest.