THE OUTER-ALPS. 
57 
as we look from such a point of vantage as the Rigi, 
we see that in reality the level is very uniform, the 
differences and the valleys being mainly due to 
denudation. Under our feet is a gigantic gravel bed 
stretching completely down to the Lake. 
Now, what are the lessons which this gravel 
teaches us? 
1. It is obviously a gravel of mountain torrents, 
but which has come a considerable distance, for it is 
well rounded, and contains blocks up to i or even 
2 feet in diameter. 
Well-rounded gravel implies transport for a con- 
siderable distance. Bonney* mentions that the gravel 
of the Stura after a course of 38 miles was still sub- 
angular, and in the Sesia after 60 miles still only 
moderately rounded. 
2 . The character of the pebbles proves that it 
has come from the south. 
3. This is also shown by the position of the 
pebbles, the flatter ones being arranged, as in modern 
streams, so as to offer most resistance to the current; 
and the position in this case shows that the stream 
came from the south. 
4. The deposition of the gravel must have taken 
a prodigious time. Not only do the beds extend 
* Geol. Mag. 1888 . 
