498 



/. Bowman — A Burled Wall at Cuzco. 



Clearly from its present condition it has been enlarged and 

 made irregular in detail through water action extending over a 

 short period of years. Though the material exposed along the 

 banks and the adjacent slopes is gravel, it stands up in steep 

 and, in many places, vertical bluffs. Its recent origin is also 

 indicated by the rapidity with which the stream, now running 

 through the ravine in wet weather, is cutting its banks and 

 carrying away alluvial material. The wall, therefore, has no 



Fig. 1. 



Fig. 1. Ayahuaycco Quebrada, near Cuzco, Peru, surveyed and drawn by 

 Kai Hendriksen. [From this Journal, vol. xxxiii, Plate II, Contributions of 

 the YalePeruvian Expedition of 1911.] 



Altitudes based on railroad survey. Contour interval, 20 feet. Scale about 

 800 ft. to 1 inch. 



necessary relation to the ravine as an artificial canal, though 

 the ends of the wall perhaps afforded modern man a clue 

 to an earlier relation between a now buried canal and the wall. 

 The main facts calling for explanation are as follows : 



(1) The buried wall runs, not down, but at right angles to an 

 alluvial slope. 



(2) It is made of blocks of cherty limestone which have been 

 cut and fitted in a rough manner, giving a face as shown in 



