PHYSIOGRAPHIC AND GEOLOGIC DEVELOPMENT 255 



our conclusions concerning the origin of the deposits and their 

 subsequent history. The sediments in the Majes Valley between 

 Cantas and Jaguey consist of three series separated by two un- 

 conformities. The lowermost series is evenly bedded and rather 

 uniform in composition and topographic expression, standing 

 forth in huge cliffs several hundred feet high on the eastern side 





1L0 



COAST RANGE 



LAS LOMftS 



s-4v\-i'C- «..-*<■;.•*.' r^r^'.v. 



LA RINCONAQA 



LAS PAMPAS 

 v STRUCTURE 



MOQUEGUA SIERRA 



UNKNOWN 











Fig. 172 — Geologic relations of Coast Range, desert deposits, and Maritime 

 Cordillera at Moquegua, Peru. After G. I. Adams; Bol. de Minas del Peru, Vol. 2, 

 No. 4, 1906, p. 20. 



of the valley. This lower series is overlain by a second series, 

 which consists of coarse conglomerate grading into sand and ulti- 

 mately into very fine fluffy wind-deposited sands and silts. The 

 lower series is much more deformed than the upper, showing that 

 the deforming movements of later geologic times have been much 

 less intense than the earlier, as if there had been a fading out or 

 weakening of the deforming agents. Finally there is a third 

 series several hundred feet thick which forms the top of the 

 section. 



Three other sections may now be examined, one immediately 

 below Cantas, one just above, and one opposite Aplao. The sec- 

 tion below Cantas is shown 

 in Fig. 173, and indicates 

 a lower series of red sand- 

 stones crossed by vertical 

 faults and unconformably 

 overlain by nearly hori- 

 zontal conglomerates, sandstones, etc., and the whole faulted again 

 with an inclined fault having a throw of nearly 25°. A white to 

 gray sandstone unconformably overlying the red sandstone is 

 shown interpolated between the lowermost and uppermost series, 

 the only example of its kind, however. No important differences 



f 



Fig. 173 — Sketch section to show structural 

 details on the walls of the Majes Valley near 

 Aplao, looking south. 



