r 



r 



Diy hills showing de- 

 posits containing gypsum. General 

 Roca, Ri} Negro, Argentina. 

 December 2, 1920. 



1432* DjTjr hills i^ith deposits 

 containing gypsum, near General 

 Roc a, E£o Negro, Argentina. 



Deceraber 2, 1920. 



B.S. 22206* Old channel of Rxo 

 Negro. Coots, Folic a armillata and 



leucoptera swimming in Yiater. 

 General Roca, Rxo Negro, Argentina. 



December 3, 1920. 



