SMITHSONIAN EXPLORATIONS, I929 I7I 



he had noted a cross identification which showed that the Puehlo 

 Bonito specimens were cut just 20 years earher than those from Aztec. 

 Now it occurred to me at the moment that if it were possihle to 

 determine the time relationship of two ancient buildings from their 

 ceiling timbers it was also possible, provided beams could be found in 

 a succession of ruins varying slightly in age, to bring together a se- 

 cjuence of annual growth rings that would extend back to the charred 

 logs of Pueblo Bonito and thus disclose the actual year in which they 

 were felled. This chance thought served as a stimulus. 



Assured of Doctor Douglass' cooperation, the Research Committee 

 of the National Geographic Society provided for a beam collecting 

 expedition in 1923, under my general supervision, and for subsequent 

 laboratory investigations. The age of Pueblo Bonito was the sole 

 objective. But that objective proved most elusive ; it was pursued 

 vigorously throughout the entire plateau country and down to Cali- 

 fornia. Naturally, the timbers from each site visited gave an in- 

 dependent ring sequence but these were gradually joined into a con- 

 tinuous record of 586 years. .Another series, from living pine forests 

 near Flagstafi:", Arizona, extended from 1925 back to A. D. 1425. 

 Next came the task of joining the modern rings with the longer, pre- 

 historic series. More material was needed and this must be pine, the 

 only medium in which Doctor Douglass could work with confidence. 



There followed a second expedition, in 1928, which confined its 

 efforts largely to the Hopi villages of north-central Arizona. Spanish 

 chronicles tell of missions constructed there during the first half of the 

 seventeenth century ; Hopi traditions relate the destruction of those 

 missions during the Pueblo revolt of 1680. Carved Spanish timbers 

 were visible in certain Hopi kivas, the subterranean chambers in 

 which ceremonies were performed by members of male societies. 

 There was just a chance that, among the largest of these pine beams, 

 at least one might be found whose rings would reach back beyond our 

 modern series to connect with the older. 



Briefly, the 1928 season produced two notable results: It extended 

 Doctor Douglass' FlagstaiT records to A. D. 1260 and it pointed out 

 the localities in which twelfth and thirteenth century ruins rightfully 

 should exist. The chief difficulty lay in the fact that such ruins, built 

 in the open, were exposed to the elements ; that their roofing timbers, 

 unless preserved as charcoal, could not possibly have survived until 

 the present. Therefore, to cross-date with material already in hand, 

 search must be made for a settlement constructed about 1275 and 

 subsequently destroyed by a fire which had been smothered by falling 



