100 G. K. Gulbert—The Colorado Plateau Province. 
ited. Or if in its progress it reaches a place where a greater 
declivity of bed gives an increased velocity, the capacity for 
transportation will become greater than the load, and there wi 
be corrasion of the bed. In this way a stream, which has a 
supply of debris equal to its capacity, tends to build up the 
gentler slopes of its bed and cut away the steeper. It tends to 
establish a single, uniform grade. 
et us now suppose that the stream, after having obliterated 
all the inequalities of the grade of its bed, loses nearly the 
whole of its load. Its velocity is at once accelerated and corre 
sion begins through its whole length. Since the stream has 
the same declivity, and consequently the same velocity, at all 
1 e. Its 
So soon as there is inequality of grade, there is inequality of 
seated and inequality of capacity for corrasion ; and where — 
ar 
In general, we may say that a stream tends to equalize its 
work in all parts of its course. Its power inheres in its fall, 
and each foot of fall has the same power. When its work is to 
corrade and the resistance is unequal, it concentrates its energy 
where the resistance is great, by crowding many feet of descent 
cludes both transportation and corrasion, as is the usual case, 
its grades are somewhat unequal ; and the inequality is greatest 
when the load is least. ; 
The condition of the Colorado in respect to load, is midway 
between that of the Niagara and that of the Platte. 
small portion of ie to the Niagara. The work of transportation 
1s at & Minimum, and the differentiation of slope dependent 0B 
rock structure reaches its maximum in a cataract. 2 
The water of the Platte is supplied with all the load it can 
move. Major Powell, who has made a careful stud 
Tiver, ascribes its peculiar character to the fact that it: 
through a region of unconsolidated strata. Its mean 
