80 STODIES HOR STLODIENTS: 
extracts. It should be noted that nearly all the writers here 
cited imply that, after baselevel is reached by a stream, down- 
ward corrasion ceases. 
McGee describes the streams of the coastal plain at about 
the head of Chesapeake Bay as ‘‘at baselevel” (1888, 617). 
Darton says, when describing the dissection of the Piedmont 
plateau of Virginia: 
As the cutting reached baselevel a series of wide terraces were cut (584). 
Winslow writes: 
The streams of the prairie country (in Missouri]... . have, in large 
part, reached baselevel, and are developing meander plains (310). 
Fairbanks states that in southeastern California: 
Erosion has reached an advanced stage with the production of excellent 
examples of baselevelling..... One of the bestexamiplesi. 7s isthe 
western portion of a granite ridge lying south of the El Paso range..... It 
is bordered by long gentle slopes of gravel and bowlders, which extending 
upward into the shallow cafions reach almost to the summit. Viewed froma 
distance of ten miles but little of the mountains appears to project above the 
plane of deposition (70). 
Salisbury’s statement is as follows: 
The time necessary for the development of such a surface is known as a 
cycle of erosion, and the resulting surface is a daselevel plain, that is, a plain 
as near sea level as river erosion can bring it. At a stage preceding the 
baselevel stage the surface would be a peneflain. .... It is also important 
to notice that when streams have cuta land surface down to the level at which 
they cease to erode, that surface will still possess some slight slope, and that 
to the seaward. Along the coast,a baselevel is at sea level. A little back 
from the coast it is slightly higher, and at a greater distance still higher. No 
definite degree of slope can be fixed upon as marking a baselevel. The 
angle of slope which would practically stop erosion in a region of slight rain- 
fall might be great enough to allow of erosion if the precipitation were 
SECALCT ante tie The Mississippi has a fall of less than a foot per mile..... 
A small stream in a similar situation would have ceased to lower its channel 
before so low a gradient had been reached (1898, 73, 79). 
J. Geikie writes: 
Running waters will continue to deepen their channels until the gradient 
by the process is gradually reduced to a minimum and vertical erosion 
ceases. The main river will be the first to attain this baselevel —a level not 
much above that of the sea (47). 
