50 



MEMOIRS OF THE CARNEGIE MUSEUM 



the U-shaped gorge cut out by the Potaro in the level plateau. The Potaro is 

 visible from time to time as it crosses from one side of the valley to the other. The 

 best view of the fall itself can be had by climbing down on a ledge of rock at the 

 edge of the precipice. I not only climbed down, but, all excitement with the fever, 



Fig. 18. Exposed left side of the bed of the Potaro River at Tukeit in the dry season. 



the steep climb, and the superb view, set up my camera on the ledge and took 

 numerous photographs. I confess to feeling distinctly dizzy when I placed my 

 head under the focusing cloth, knowing that if something should happen I and the 

 camera would land on the rocks a thousand or so feet below. Not that I could 

 find a finer place to die, but I was reluctant to start to " kingdom come " on such a 

 heavy down grade. 



After making about thirty exposures under varying conditions, we went to 

 the camp in the bush some distance up the river. The fall is caused by an exces- 

 sively hard conglomerate which overlies a softer sandstone. The savannah above 

 the fall is in large part this naked conglomerate. In places bushes grow from 

 cracks in the rocks. Many bunches of grass, or flowers grow from a little accumula- 

 tion of soil that can be kicked from place to place along the surface of the rock. 

 The afternoon of the 18th and part of the 19th were devoted to fishing and packing. 



