ANALYSIS OF TERRESTRIAL RECORDS 



105 



Sequoia Chronology Cycles — Concluded 



The author's analysis of the sequoia chronology was largely done in 1918; this was 

 reviewed more recently at various times. Mr. Schulman did this work on these data in 

 the last year; the tabular matter here given is based on Mr. Schulman's results, checked 

 by the author's. Amplitudes have been worked out under the direction of Dr. W. S. 

 Glock, Mr. Edmund Schulman, and Mr. G. C. Baldwin. 



CENTRAL PUEBLO CHRONOLOGY 



The sequoia chronology just described is taken from continuous tree 

 records of extraordinary length: four of the trees show more than thirty 

 centuries and large numbers reach 2000 years. In sharp contrast, the Arizona 

 chronology is built of a large number of overlapping records matched together 

 by cross-dating of ring groups. It would perhaps be difficult to find another 

 locality where this could be done. It was accomplished by the interest and 

 generous aid of the archaeologists. A partial account is given elsewhere. 1 



Besides the National Geographic Society, other institutions and persons 

 gave important help: the American Museum of Natural History in New 

 York City, the Museum of Northern Arizona, Dr. and Mrs. Colton at Flag- 

 staff, the University of Arizona, the Carnegie Institution of Washington and 

 many interested students and friends. The archaeological phase started in 

 1914 and in 1929 passed a milestone in the closing of a "gap" between dated 

 records extending back to or a little before 1300 and a "floating" chronology 

 extending back to what later proved to be A.D. 700. This gave to the 

 climatologist a bio-climatic record back to that time. The extension back 

 to A.D. 11 and the needed strengthening in the early Eighth Century came 

 very largely from the splendid collections of Mr. Earl H. Morris between 

 1927 and 1933. 2 



Definite work on the portion of this chronology before 700 began in May 

 1931 and its accuracy was considered assured by the late summer of 1934. 

 Yet certain confirmations in Flagstaff specimens examined in February 1935 



1 Dating Pueblo Bonito and Other Ruins of the Southwest, Technical Monograph 



Eublished by the National Geographic Society; Paper Number 1 in the Pueblo Bonito 

 eries. See also the earlier account : The Secret of the Southwest Solved by Talkative Tree 

 Rings, Nat. Geog. Mag., Dec. 1929. 



2 The valuable collection work of Mr. Morris was aided by the Carnegie Institution 

 of Washington, the American Museum of New York, the University of Colorado, Mr. C. 

 L. Bernheimer and others. A specially valuable specimen was collected by Dr. Flor- 

 ence M. Hawley while giving field instruction in connection with the Department of 

 Archaeology of the University of New Mexico. Other aid is mentioned on pages 6-7. 



