DEPARTMENT OF BOTANICAL RESEARCH. 53 



northern, and northwestern parts of New Mexico. The purpose of these 

 visits was to obtain a first-hand knowledge of some of the areas where arche- 

 ologists are most actively at work, in order that the results of archeological 

 and geographic studies may be brought into harmony. In this work Dr. 

 Huntington received the cordial cooperation of the American Archeological 

 Institute through the curator of its museum at Santa Fe, Mr. Kenneth M. 

 Chapman. The last piece of work in New Mexico was a visit to the so- 

 called prehistoric dam of colossal size which has been reported by various 

 travelers in the extreme southwestern corner of the State. The dam proved 

 to be unquestionably the work of nature, not of man. It is merely an old 

 lake strand, although it has been described by other investigators in detail as 

 the work of human hands. A number of ruins were found in the region, 

 however, proving that a fairly abundant population once existed even in this 

 out-of-the-way corner. 



The two months spent by Dr. Huntington in California were devoted to 

 minute measurements of the thickness of the rings of annual growth of giant 

 redwood trees, which have been cut for lumber during the past generation. 

 In this he was assisted by H. E. Miller, of Elk Grove, California, and D. B. 

 Cohen, of Oakland, California. About 200 stumps were measured, varying 

 in age from 2,300 to 3,150 years; 42 of these trees began their growth more 

 than 2,000 years ago, and three more than 3,000 years ago. The thickness of 

 the growth was measured for each decade from the beginning to the present. 

 The 40,000 numbers thus obtained are being examined, and from them it 

 will be possible to prepare a curve showing, with considerable clearness, the 

 main climatic fluctuations for at least 2,000 years. Preliminary partial com- 

 putations indicate that this curve will show close resemblance to the climatic 

 curve computed from evidence of a totally different character obtained in 

 Asia. In order to test the matter more fully, trees of other species are being 

 used, not only in California, but in various parts of the United States. For 

 this purpose the United States Forest Service, through Mr. H. S. Graves, 

 Forester, has placed at the disposal of the Institution all its thousands of 

 stem analyses, many of which were taken from trees 2 to 1,200 years of age. 

 The curves derived from all of these will be published with those of the 

 sequoias in the report on the ancient climate of America, which is in prepa- 

 ration by Dr. Huntington, 



Inductive Influence of Climatic Complexes upon Organisms, by 

 Dr. D. T. MacDougal. 



The comparative culture of a number of selected species in the desert, 

 maritime, and montane plantations are already yielding some facts of wide 

 interest as to possibilities in geographic movements in addition to the envi- 

 ronic reactions, the determination of which is the prime purpose of the in- 

 vestigation. Thus perennial forms native to the lowlands of eastern Amer- 

 ica (with a growing season of 168 to 170 days and a winter with extended 



