nota 
VIII RIVERS AND LAKES 289 
over, is perhaps the more interesting as being 
evidently very recent. . ; 
“Mr. Gill,” he says, “mentioned to me a 
most interesting, and as far as I am aware, 
quite unparalleled case, of a subterranean dis- 
turbance having changed the drainage of a 
country. Travelling from Casma to Huaraz 
(not very far distant from Lima) he found a 
plain covered with ruins and marks of ancient 
cultivation, but now quite barren. Near it 
was the dry course of a considerable river, 
whence the water for irrigation had formerly 
been conducted. There was nothing in the 
appearance of the water-course to indicate 
that the river had not flowed there a few 
years previously ; in some parts beds of sand 
and gravel were spread out; in others, the 
solid rock had been worn into a broad chan-— 
nel, which in one spot was about 40 yards in 
breadth and 8 feet deep. It is self-evident 
that a person following up the course of a 
‘stream will always ascend at a greater or less 
inclination. Mr. Gill therefore, was much 
astonished when walking up the bed of this 
ancient river, to find himself suddenly going 
U 
