GEOLOGY AND TOPOGRAPHY OF THE RIO GRANDE 

 REGION IN NEW MEXICO^ 



By Junius Henderson 



IN the present age of railways and machinery the location of new 

 villages, towns, and cities is controlled to a much greater extent 

 than formerly by transportation lines and the proximity of 

 products of commercial value. Cities may now be readily built in 

 inhospitable deserts or other unfavorable localities where there are 

 no good building materials, food products, or surface water, the 

 former two being transported from great distances by i:ailways and 

 the latter being obtained from deep wells made possible by boring 

 machmery or piped from remote sources. In more primitive times, 

 when the proximity of a suitable water supply, tillable lands, and 

 building materials was necessary and ease of defense was important, 

 geologic phenomena and topographic features were leading factors 

 in the location of permanent habitations. The flow of water from 

 permanent springs or perennial streams, easily defended cliffs or 

 canyons, drainage, and lands suitable for agricultiu'e are the direct 

 results of geologic processes. Even the climate and the natural dis- 

 tribution and abundance of wild animals and native plants, which 

 may form part of the food of a village population, are directly or 

 inchrectly influenced by geology and topography. Hence a study of 

 these features in a region such as the one under consideration is 

 necessary to a full comprehension of the environment and culture of 

 its ancient inhabitants. 



El Rito de los Frijoles, where the studies embodied in the present 

 report were chiefly carried on, is a small rivulet flowing through one 

 of the many canyons that dissect the Jemez plateau on the western 

 side of the Rio Grande, north of west from Santa Fe, New Mexico. 

 It is taken as a t}^)ical canyon of the region. 



The general region is the Rio Grande basin in northern New Mexico, 

 a broad valley lying between the Santa Fe mountains, which form 

 the southward extension of the Sangre de Cristo range, and the Jemez 

 mountains, which form the southward extension of the San Juan 

 range. These tw^o ranges well to the north in Colorado are composed 

 of very high peaks, but in passing soutluvard into New Mexico they 



1 See Bandelier, A. F., Final Report of Investigations Among the Indians of the Southwestern United 

 States, Papers Archxol. Inst. Amcr., Amer. ser., iv, 139-41, 1892; Hewetl, Edgar L., The Excavations at 

 Tj-uonyi, New Mexico, in 1908, in ^ mfr. Anthr., xi, 434-55, 1909 (Papers School A mer. ArchseoL, no. 5). 



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