I. Bowman — Physiography of the Central Andes. 215 



of interest to note how generally it occurs in other parts of the 

 central Ancles. 



While opportunity was not afforded to study in the same 

 detail the interesting plateau section east of Arica, Chile, 

 the photographs of the plateau, fig. 11, made from the summit 



Fig. 10. 



Chatarilla ^'"t-s 



Fig. 10. — Detailed view of southern end of sketch, fig. 5, looking east 

 from Allianza, Chile. 



of the 1000 ft. hill northeast of the port of Arica, will suggest 

 with what probability the peneplain is known to occur in this 

 locality. The views include about 50 miles of country. The 

 14,000 ft. (?) tableland constituting the summit of the Cordillera 

 (beyond the left of the photographs) is so flat that this quality, 

 and not the lofty snow-capped peaks surmounting the tableland, 

 forms, physiographically considered, the most conspicuous fea- 

 ture of the landscape. With what structural quality the descent 

 is made to the intermediate level in the photographs, and what 

 the genetic relation of these two tablelands is, was not deter- 

 mined. From the detailed geomorphic study made directly 

 south, of similar relations, it is not an unreasonable assump- 

 tion that the two surfaces were once continuous and that the 

 zone of displacement is represented by the descent from the 

 upper platform. 



The lower wind-swept platform of this vicinity presents a 

 hard-featured landscape of remarkable flatness, now deeply 

 covered with drifting sand, now roughly cloaked with angular 

 fragments, from which the line material has been sifted by the 

 constant wind. It is wonderfully impressive to one who conies 

 prepared to see a line of precipitous volcanic heights to find 

 these great flat-topped tablelands dominating the view, only 

 partially relieved toward evening by the fine appearance of 

 the distant snow-capped peaks. 



Again at Crncero Alto (14,000 ft.), Peru, on the railway from 

 Puno to Mollendo, one rises well towards the level of the great 

 plateau and sees extending out in every direction the topog- 

 raphy suggested by fig. 32. For physiographic purposes it 

 would be useless to describe the structure in any detail, so 

 universally complicated is it. But in spite of the enormous 

 plications and irregularities everywhere observable the upper 



