310 ANNUAL, REPORT SMITHSONIAN INSTITUTION, 19 31 



chronology in Arizona pines, which has not only furthered our 

 studies of climate but has supplied the building dates of a number 

 of prehistoric ruins. 



This chronology building has been done on the numerous speci- 

 mens which the archeologists have obtained from prehistoric ruins 

 since 1922. These came chiefly from Neil M. Judd, who was excavat- 

 ing Pueblo Bonito on behalf of the National Geographic Society. 

 He had learned of the cross dating between diiferent ruins and rea- 

 lized that such cross dating could be carried from the present time 

 back into prehistoric ages, thus giving the actual date of the great 

 ruin in whose repair he was engaged. His faith in the possibility 

 of such dating resulted in important assistance from Doctor Gros- 

 venor and the research committee of the society. And this, together 

 with occasional friendly aid of other institutions, brought in large 

 collections of prehistoric beams, which reached over 800 in number 

 by 1928. These cross dated in large measure and supplied a prehis- 

 toric chronology 586 years long, and in doing so gave the relative 

 age of more than 30 prehistoric ruins from which the specimens 

 had come. 



The problem of finding material to fill the gap between the prehis- 

 toric chronology and the historic sequence extending back to 1260 

 A. D. occupied us in the field trips of 1928 and 1929. Large collec- 

 tions were first obtained from the Hopi villages, the Pueblo struc- 

 tures which were still occupied by the Indians. The village of 

 Oraibi, which 40 years ago had 900 inhabitants, was discovered to be 

 over 500 years old. It is now largely abandoned. 



But the Hopi beams did not show rings that extended back far 

 enough, so we searched and found the ruins from which some of 

 these Hopi people came. Thus, we succeeded in getting the first 

 prehistoric dates at the ruin of Kawaioku, in the Jeddito area. The 

 dates extended from 1357 to 1495. In preparation for 1929 we 

 studied pottery chronologies and found that the beams in the gap 

 would be associated with an orange-colored pottery, which was a 

 transition from red to cream color. We also concluded that the exist- 

 ence of charcoal was very important on account of its wonderful 

 preservations. Therefore, we must find ruins near the border of the 

 great pine forest. 



These conditions were best fulfilled at Showlow and Pinedale, 50 

 miles south of Holbrook. The actual gap beam was found at Show- 

 low, June 22, 1929. It showed the well-known rings in the 1300's, 

 then the group of microscopic rings during the drought in the late 

 1200's, then a splendid series to the central ring that grew in 1237. 

 The early drought years identified on this piece were entered on our 

 plots as an extension of the historic series, and that evening the com- 



