S84 ANNUAL REPORT SMITHSONIAN INSTITUTION, 1912. 



four months in 1911, and four in 1912, have now been spent in the 

 field. The time was divided between the States of New Mexico, 

 Arizona, and California in the United States, and Sonora, Mexico 

 City, Oaxaca, and Yucatan m Mexico. Most of the methods of 

 investigation were similar to those which the writer has employed 

 in Asia, and led to a similar result. To these, however, were added 

 some significant observations upon the relation of tropical jungle 

 and tropical forest to civilization in Yucatan, and a series of highly 

 conclusive measurements of trees. Both of these new and inde- 

 pendent lines of observation confirm previous conclusions, but in the 

 present article the facts as to Yucatan must be omitted for lack of 

 space. 



Omitting all consideration of the effect of climatic changes upon 

 the form of the earth's surface, the composition of soU, the distribu- 

 tion of animals, and various other lines of thought, let us turn at 

 once to the vestiges of pre-Columbian man found in the southwestern 

 part of America. Some, such as the cliff dwellings and the great 

 irrigation works and villages of the Gila Valley in southern Arizona, 

 are famous. A far larger number, however, have received almost no 

 attention even from archeologists. The reason is obvious. In most 

 cases the ruins are so insignificant that an unobservant traveler might 

 ride miles through what was once a region thickly studded with vil- 

 lages \vithout being aware of the fact. Walls for defensive purposes 

 upon the mountains or pictographs upon the face of the rocks are apt 

 to attract attention, but few people notice the far more important 

 sites of villages scattered in profusion over thousands of square miles, 

 especially in southern Arizona, New ]\Iexico, and the neighboring 

 parts of Sonora. The sites are now reduced to barren expanses 

 strewn with ornamented bits of pottery, flint knives and arrow heads, 

 stone hammers and axes, mani and metate stones for grinding seeds, 

 and in some cases rectangular lines of bowlders placed erect at inter- 

 vals of a foot or two and evidently outlining the walls of ancient 

 houses. Here and there a little mound a foot or two high shows 

 where an ancient dwelling was located. In almost every village an 

 oval hollow surrounded by a low wall covers an area 100 or 200 feet 

 long by half as wide — not a reservoir, as one at first supposes, but 

 probably a ceremonial chamber of some sort. Aside from these 

 scanty traces nothing remains. Yet there can be no question that 

 these weye once ancient villages. Frequently the ground is full of 

 bits of pottery to a depth of 2 feet or more, wliile the surface is so 

 strewn with similar bits that one can not walk without treading on 

 them. The houses were probably built for the most part of branches 

 wattled with mud. Such houses disappear quickly when abandoned, 

 for the wood decays and the clay used for wattling blows away or else 

 is spread over the ground in such a way as not to be noticeable. The 



