176 SMITHSONIAN INSTITUTION 



Bonitians, like other Pueblo builders, added to their terraced town 

 as necessity required. They razed and replaced dwellings with sur- 

 prising disregard of the physical labor involved ; logs they felled and 

 trimmed with stone axes were used over and over again. As evidence 

 of conservative Pueblo habits it is interesting to note that, in Oraibi, 

 Doctor Douglass uncovered a ])ine timber which had been utilized 

 more than 500 years. 



That the better informed archeologists. tracing the development 

 and spread of Pueblo civilization, know whereof they spoke is well 

 indicated Ijy the Douglass tree-ring chronology. For example. Cliff 

 Palace, in the Mesa Verde National Park, Colorado, was recognized 

 by many as among the oldest major cliff-dwellings of the Southwest 

 yet distinctly younger than Pueblo Bonito ; Betatakin and Keet Seel, 

 out in the northern Xavajo country, were regarded by the same 

 authorities as perhaps the last inhabited cave ruins of the San Jnan 

 drainage. Now we know absolutely, from the mute record of their 

 ceiling beams, that at least one log was cut for Cliff Palace in A. D. 

 1073; that Spruce Tree House was inlial)ited nearly two centuries 

 later ; that White House pueblo, in Canyon de Chelly, dates from 1060 

 to 1275 ; that 13 timbers were felled for Betatakin during the 17 

 years following A. D. 1260; that the seven Keet Seel logs represented 

 in our collection were cut in the decade beginning 1274. 



Thus in seeking the date of Pueblo Bonito, the National Geographic 

 Society expeditions have ascertained the ages of approximately 40 

 other ruins. Given beam samples, charred or otherwise, with outside 

 ring intact, almost any prehistoric southwestern settlement may be 

 brought within our modern calendar by the Douglass chronology. 

 Material is already in hand from Basket Maker sites ; from Pueblo I 

 ])it dwellings. It remains only to bridge the gap between them and 

 the oldest annual growth ring found in Pueblo Bonito before we can 

 time the beginnings of sedentary life in the Southwest and the in- 

 ception of agriculture. 



In the December. 1929, issue of the National Geographic Magazine 

 Doctor Douglass tells the story of the Society's three beam expeditions 

 and something of their results. Plis more complete presentation, in- 

 cluding a description of methods, will accompany my own report on 

 the Pueblo Bonito explorations, now in preparation. Not until this 

 latter volume is issued can adequate recognition be given those several 

 individuals who have generously contributed to the success of this 

 magnificent undertaking. 



