AND THE VICTORIA NYANZA 



58 



or five miles round the mountain mass at this altitude (an average 6,000 

 feet), it not infrequently happens that the mouth of a cave exactly coincides 

 witli the descent of a waterfall from the edge of the precipices far above, 

 the water thus serving as a curtain to screen the mouth of the cave from 

 sight when viewed in front. The native path leading to the cave will thus 

 take you dry-shod under a river, and when you are seated at the mouth of 

 a cave you may see the splendid glowing landscape of the plains through 

 an opal-tinted veil of water. What is the origin of these caves ? One 

 can state no precise o[«iniou with our present limited information. It is 



\Mi ri;ij'ii'rnas (.'i.iffs 



true that these recesses at the base of the precipitous terraces so often 

 coincide with the overhanging cascade of a river that quite possibly tiiere 

 may liave been at one time a percolation of the stream from above, through 

 the crumbling rock, which hollowed out these caverns. Later on, some 

 cement-like material brought down by the water from above, or some lava 

 flow, may have completely closed the.sie cracks through which th.' [)ercolation 

 took place, with the result that the .stream once burrowing througli the 

 cave now flows in a shallow rock cliannel high above it, and dashes itself 

 in sheer falls of 100 feet or more, arching over the nioutli of the cave, 

 and continuing its course along a less precipitous gorge below. Certainly 



