RIVER TERRACES. 671 
Cowlitz River, - a s 6 5 A0 to 45 feet. 
Columbia, at Vancouver, - : = - 45 feet. 
Columbia, at Wallawalla, — - - - - 150 (2) feet. 
Columbia, south of mouth, é = : 35 feet. 
Willammet River, - - - - - 50 to 60 feet. 
Umpqua River, - : - - - - 15 feet. 
Shasty River, - - - - - - 20 feet. 
Sacramento, - : 2 E 2 - 60 or 70 feet, and — 
country rising gradually above the slope to two hundred feet. 
There appear to be but two ways of accounting for these river ter- 
races: either lakes have existed along the rivers, which have burst 
their barriers, or the rivers have excavated the country in consequence 
of an elevation. 
The existence of lakes throughout a whole country, connected 
with all its rivers, is highly improbable, and requires for its proof the 
strongest evidence. Rivers cut out their channels by a gradual pro- 
cess, aS a country is raised above the ocean, forming, with few excep- 
tions, a complete drainage for the land. Lakes could not, therefore, 
exist to the universal extent implied by the facts, except, perhaps, as 
the result of a sudden rising of the land from the ocean. 
The formation of such lakes, by an abrupt elevation, in a region 
having the ranges of heights parallel with the coast, as in Oregon, is 
certainly a possibility. But the water, to make the alluvial accumula- 
tions, must be running water, and it must be in operation in its chan- 
nels for a long period. And how long would such lakes exist after an 
elevation? If the violence attending the change of level did not at 
once open for them a passage, the accumulation of water going on 
during a single flood, would break a passage through such soft sand- 
stone beds as occur about the mouth of the Sacramento.* ‘The valley 
of the Sacramento is one hundred and fifty miles long, and twenty to 
fifty miles wide; and is it possible that this vast area could have been 
filled with waters, and they not soon have channelled out a course 
through a low sandstone barrier near the sea? If the reader will bring 
before him the necessary circumstances attending such phenomena, 
the impossibility of this mode of forming these flats will be evident. 
But we are not left to this kind of evidence alone. 
These terraces on the Sacramento occur toa distance of at least one 
* This river enters the Bay of San Francisco through the Caquines Straits, which are 
a. mile wide and three long, and are bounded by hills and bluffs of soft sandstone, one to 
three hundred feet high, 
