174 ATABAPO AND UPPEK EIO NEGKO. 



tion ; while upon its remaining sides, that sloped more 

 gently, bushes and dwarfed forest-trees partially clotlied 

 the otherwise barren walls. The traveller on the Upper 

 Rio Negro frequently has his attention attracted by these 

 curious, isolated, granitic masses, which often, in tall pillars 

 or gigantic towers, clothed with little or no verdure, rise 

 abruptly from the surrounding forest-level, forming a 

 striking feature in the monotonous landscape. 



