New Britain herald., 1929-10-30
TREES GIVE CLUES
 ID ANCIENT DATES
Provide Calendar for Placing
 Pre-COlumbian Indian Ruins

Washington, D, C., Oct, 30-Dat- 1 ing the occupancy period of the fla nous Pueblo Bonito in Chaco Can yon, New Mexico, giant communal dwelling which has been called Americas first apartment house, and of some 40 other major pre- Columbian ruins Of the American southwest is in immediate prospect. according to an announcement made today by Dr. Gilbert Grosvenor, president of the National Gcograph- ical society.
 Study and codifcation of about 5000 tree sections. including ser ics of cross sections located this summer after years of search. is be- ing concluded by Neil NJ. Judd. lead CT of the National Geographic so- ciety's expeditions which revealed Pueblo Bonito, and by Dr. A. F.. Douglass. leader of the timber and wooden beam research parties which are about to yield the answer to Americas foremost archaeological problem.
 These scientists and their aids, the National Geographic society ex- plains, are about to write the final answer to "scientifc detective story" that has progressed through chapter after chapter until this summers work eliminated in find ing the missing tree ring links that spell the solution.
 This solution will enable the so ciety to date the period when the complex and highly developed civili- zation of Chaco Canyon reached its continuation in the Beautiful Village Pueblo Bonito), q communal dwell ing of some 2,500 people, centuries before the white man set foot on American soil. There this aboriginal people. with no apparent communi- cation with the Egyptians, Babylo- nians or Assyrians, constructed thelr masonry residence, equipped it with household utensils. furnished ccre- monial chambers, and wrought in tricatc jcwelry of marvellous beauty. Yields Many Art Treasures These memcntoes of civilization which rivaled those of the ancient Old World cultures. of which the Bonitans apparently knew nothing, have already been brought to Wash ington from year to year. and have been viewed by thousands and pie tured in publications the world over.
 But always there was the per picking question about Pueblo Bon ito, as about the other pre-Colum- bian ruins, How old are they?"
 Archaeology, botany astronomy, micro photography and plaln "sleuthing" were brought to play to solve this scientific mystery. The trail led along the tree-rings pa tiently collecting from sections cut in various parts of the Southwest, to be compared with similar rings found in the ancient wooden beams of Pueblo Ronito itself.
 Years of painstalling research were based on the commonly known | fact that tree growth deposits a ring i for each year of the trees life, and under a miscroscope each years ring shows individual characteris- ties. Lean years or fiat" years, in terms of rainfall and consequent tree nouriShment, are registered in dclibly and unmistakably.
 Therefore it follows that trees which have grown in the same re- zion, 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 comparison. The life of single tree in New Mexico will not span many centur- ies. But an old tree and a young tree, growing side by side, will reg ister the same season 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 Bonito, and those of other ruins, and by match ing the overlapping sections of one series with another until the record l was linked up with sections of liv- ing trees, reconstruct the tree-ring calendar.
 Solution Near, But BafYling When this seasons work started the scientists were so near solu- 1 tion that the lapse in their records was all the more baffling. They had worked back a chronology after years of patient study of old tim bcrs and sections of living trees that gave them a calendar to 126O A. D. They had established another chronology covering a pre-Colum- bian period Of 5SG years.
 All so far proven was that Pueblo Ronito dated some time before 1260. To get exact dates it was nee essary to dovetail the two chronolo- gies. Is there a gap between? Or dc they overlap?
 Photographic advices to Dr. Gros- venor gives assurance that the tim Der sections collected this summer are adequate to link the two calen- dars, and thus solve major prob lem affecting all the important pre- Columbian ruins of the Southwest.