I. Bowman — Physiography of the Central Andes. 391 



the similarity of the views and descriptions. All about 

 Cochabamba and on the way to the divide toward Oruro, in 

 the Cliza basin, in southern Peru, between Lake Titicaca and 

 Cuzco, north of Inca Corral, in each one the same relationship 

 between slopes exists as may be found in all the others. The 

 two localities described below, Cliza, and the upper Urubamba 

 valley in southern Peru, are farthest apart (475 miles in 

 a straight line), the one in the eastern Andes, the other in the 

 western Andes, and they will therefore serve to show, not only 

 the correspondence of features and development thus far 

 described, but also the correspondence of development between 

 the eastern and western Andes. 



The Cliza basin lies due southeast of Cochabamba (see map, 

 fig. 21). It is enclosed by a rim of "cerros" or hills and is 

 drained by the Cliza and Arani rivers, headwater tributaries 



Fig. 23. 



Fig. 23. Flat-topped spurs on northern border of Cliza basin, Bolivia. 



of the Rio Grande, one of the major streams of Bolivia. The 

 Cochabamba and Cliza basins are alike in consisting of 

 Devonian sandstones rimmed about by Silurian quartzites and 

 schists. A deep accumulation of alluvium is found on the 

 floors of both basins. Both are drained by outlet streams 

 whose old rock-cut and gravel-strewn terraces several hundred 

 feet above the present levels of the streams at the narrow 

 outlets of the basins represent the level of the drainage at the 

 close of the second cycle of development, during which the 

 slopes of maturity were formed. These terraces are particularly 

 well developed five miles west of Arcaji, in the narrow gap 

 through which the basin waters are discharged. About the 

 margins of both basins the slopes have the appearance of ~Rg. 

 23. The sketch is traced from a field drawing made from a 

 point near the center of the basin looking north by west at the 

 edge of the surrounding hills, west of the village of San 

 Benito. Table-topped spurs descend from the broad crest of 

 the rim (800 to 1500 ft. above the basin floor) by gentle 



