116 



BUREAU OF AMEEICAN ETHNOLOGY 



[bull. 52 



be even entirely covered, and that not merely in the surface of the 

 black, but also in that of the gray, playas, for cattle, horses, ostriches 

 (rheas) and other animals occasionally visit these depressions, and, 

 especially after rains, may press small stones into the ground ; or rain 

 water and the wind may contribute, by means of the material wliich 

 they carry, toward the same end. On the playas south of Punta 



Xa^tcrva. die los Padres 



PROVINCIA DE 

 BUENOS AIRES 



Laguna. CorrierUes 



Fig. 2. Map of the Argentine coast from Mar del Plata to the Barrancas de los Lobos. 



Mogote, Mr. WiUis and the writer observed several worked stones, 

 as well as some recent bones, banked on the windward side with 

 fine wind-blown material of the same color and apparently of the 

 same geologic nature as the deposits underneath. After a rain such 

 accumulations might easily harden and thus appear as constituent 

 parts of the older ground on which they are formed. 



