866 



SCIENCE 



[N. S. Vol. XLI. No. 1067 



constants, sun-spots, the prices of wheat, size 

 of crops, growth of trees and comparative tem- 

 perature fluctuations at various points of the 

 earth's surface, contributes to support the con- 

 elusion that the " solar hypothesis," meaning 

 the occurrence of sun-spots and a correspond- 

 ingly cyclic change in the sun's radiation are 

 sufficient to and do account for the causation 

 of measurable meteorological results. The 

 larger question of climatic change during the 

 vast extent of geological time is attacked by 

 Dr. Charles Sehuchert in a paleometeorological 

 monograph incorporated into the volume as 

 Part II., in which the crustal deformation of 

 the earth due to gravitational agencies is seen 

 as the cause of change and redistribution of 

 climatic zones. It seems conclusive that pe- 

 riods of mountain-making have been followed 

 by cooler times, though, as Huntington and 

 Sehuchert both admit, there still remains the 

 difficulty of accounting for the apparent causal 

 relation between these, for the minor fluctua- 

 tions of climate which are now in progress, and 

 for the interglacial climates characterized by 

 higher temperatures. At this point the solar 

 hypothesis appears to articulate with that of 

 crustal deformation. A full and impartial 

 discussion of all the theories, in itself quite 

 exemplary, strengthens the authors' positions, 

 but for these details the original volume must 

 be examined. 



There remains of the reviewer's task a neces- 

 sarily brief and equally inadequate mention 

 of the body of evidence from the point of view 

 chiefly of human activity, but including certain 

 topographic facts. 



The salient condition for the studies lies in 

 the sensitiveness of the semi-arid desert to 

 apparently minor deviations from the normal 

 course of rainfall, and, for the author's pur- 

 pose, its effect upon human economy. That 

 these fluctuations of precipitation have oc- 

 curred, there is abundant evidence in records, 

 and in the fate of modern enterprises ; and, ac- 

 cording to Huntington, in the making of ter- 

 races, new and old, but all embraced within 

 comparatively recent times, which can be seen 

 at the present time well illustrated in the Santa 

 Cruz Eiver at Tucson, in the different levels 

 of lake beds, in the fixation of older and move- 



ment of later sand dunes, as illustrated in the 

 White Sands of the Otero basin and in the 

 different ages of ancient aboriginal villages. 

 Evidences of an earlier large population were 

 studied in localities found in the whole wide 

 region from south New Mexico to northern 

 Sonora. The close examination of these evi- 

 dences is so masterfully done, and with such 

 intimacy of touch, that one feels, as it were, a 

 thread of drama running through it. While 

 the contemplation of history seems to lengthen 

 the years agone, that of the earlier culture of 

 the desert seems, in these studies, to bring us 

 nearer to the past. In particular, the account 

 of the condition on the lower Altar may be 

 cited in illustration of method and treatment. 

 This valley, beginning at the village of Altar 

 and ending at Disemboque on the Gulf of Cali- 

 fornia, contains a string of villages either occu- 

 pied, as Caborca, with 1,500 inhabitants, and 

 Buzani with a mere handful, but with the 

 riiins of a mission, or uninhabited — and recog- 

 nizable only from the itsual signs — artefacts, 

 foundations, canals, villages extensive enough 

 to accommodate 1,500 folk, perhaps more. 

 Lands now either cultivated opportunistically, 

 but less and less as the gulf is approached or 

 not at all, but always extensive enough for the 

 support of large numbers of the primitive peo- 

 ple, together with signs of irrigation works, 

 combine with the ruins, to form a setting for 

 a numerous people. But the people are not 

 there. All the facts point to a condition when 

 agriculture was possible and water was in 

 quantities sufficient to supply the villages by 

 means of canals, in the absence of wells (as 

 at Buzani). A feature of especial interest 

 described is the curious terraces or trincheras 

 found at various localities. These merge with 

 rectangular areas, discernible now only from 

 an eminence, on the lower gentler slopes. 

 These trincheras were undoubtedly for agri- 

 cultural use, and this view taken by Hunting- 

 ton, receives support from the occurrence of 

 similar trincheras observed by the reviewer 

 in the fastnesses of the Sierra Madre of Chi- 

 huahua, associated with the ruins of ancient 

 villages. But if for agriculture, whence the 

 water? A little arithmetic shows pretty con- 

 clusively that they could not have been irri- 



