312 annuaij report Smithsonian institution, 19 31 



Crater near by. He has already been able to make a rough estimate 

 of the date of this eruption, and there seems little doubt that eventu- 

 ally it will become known with accuracy. 



CLIMATE AND PREHISTORY 



From the foregoing it is evident that prehistoric dating has become 

 possible through weather effects in the rings of trees. Hence we not 

 only get the dates of building periods in the history of the pueblos, 

 but also we obtain some idea of the accompanying meteorological con- 

 ditions. This has given us a strong impression of climatic stability, 

 for there is no real evidence of any fundamental climatic change. 

 The mean ring growth of a thousand years ago was not greatly 

 different from that to-day in the same region. 



But there are signs of strong pulsations or cycles. In each hun- 

 dred years there has been a noticeable drought. Every third century 

 has seen a very great drought, such as 1880 to 1904, 1573 to 1593, and 

 1276 to 1299. The effects of these come to us in notably defective 

 trees and in abandoned pueblos. In the 500-year history of Oraibi 

 even the small droughts were accompanied by decreased building. 



But perhaps the most significant inference is a combination of 

 these two. Though the climate can not be said to be changing, the 

 pulsations do not in all cases return completely to the earlier condi- 

 tion, for in certain areas there seems to be a drying out due to human 

 occupation. From studies of change in ring types and from many 

 interesting conversations with the Pueblo Indians we can reconstruct 

 a part of this story of human adventure in a dry country. It is prob- 

 able that the primitive people settled on the forest border to get best 

 advantage of timber, water supply, and farm lands. They injured 

 the forest by cutting trees for house building and caused the forest 

 borders to retreat. This injured the ground cover and permitted the 

 soil to blow away until the conservation of moisture was decreased 

 and torrential rains tore up their farm lands and compelled them to 

 migrate to new locations. This has actually happened in the last 40 

 years. Thus we find in this primitive history a human cycle of deep 

 meaning for us who, even as these Indians, show an inclination to 

 exhaust our natural resources without sufficiently generous thought 

 for the future. 



REMARKS OF CHIEF JUSTICE CHARLES EVANS HUGHES 



Chancellor of the Smithsonian Institution 



Doctor Antevs : You have come to us from another land and clime where 

 your early studies, guided by that pioneering scientist, the Baron de Geer, 

 contributed greatly to our knowledge of the progress in Europe of that world- 



