170 ELEMENTARY GEOLOGY 
of the large and small falls of Europe and America, 
—such, for instance, as those of central New York 
(Frontispiece and Plate 7), St. Anthony and Minne- 
haha, in Minnesota, and thousands of others! (Fig. 84). 
The Colorado Cafion. — 
The most marvellous river 
valley in the world is that 
of the Colorado of the West 
(Figs. 85 and 86). This 
river flows through steeply 
rismg, rock-bound walls, 
over a grade of nearly 
eight feet to the mile, 
always carrying large 
quantities of water and 
sediment, and at times 
becoming a raging tor- 
rent, which sweeps along 
Fia. 85. not only finer materials, 
A soone 1 tne scopes Part of the but pebbles and bowlders. 
It is still deepening its 
valley at a rapid rate, and for three hundred miles 
flows in a canon, which it has carved, whose walls 
rise to a height of from one thousand to several 
1 While this is the most common cause of waterfalls, it must not be sup- 
posed that it is the only one. Space prevents further consideration of the 
subject here; but a somewhat more complete statement may be found in 
the author’s Hlementary Physical Geography. 
