104 STUDIES FOR STUDENTS 
that such an implication aroused, that the term peneplain was 
suggested thirteen years ago. This word gradually came into 
use with quotation marks and an explanatory footnote. The 
footnote disappeared first, and now the quotation marks are 
frequently omitted as if the word had gained an established 
position, although among writers in Great Britain the need 
of the term is still so little felt that it is generally men- 
tioned as an American invention when used at all, instead 
of being fully adopted, like delta and atoll, without explana- 
tion or acknowledgment. . 
There seems to be today less hesitation regarding the 
acceptance of the idea of far-advanced subaerial degradation 
than there was fifteen years ago—witness the use of ‘plain 
of erosion” by Hobbs (137) as a name for the worn-down 
surface, now uplifted and dissected in the uplands of Con- 
necticut; nevertheless it still seems desirable to speak of such 
surfaces as peneplains in the absence of proof that they were 
actually reduced to plains. The alternatives for peneplain 
are as follows: 
Powell contrasts ‘‘gradation or true plains’ 
phic plains” (plateaus), the former being produced by gradation, 
” and the 
d 
with ‘ diastro- 
a ‘‘ process accomplished through the agency of water, 
latter by the uplifting of the earth’s crust. This use of ‘‘ grada- 
tion’’ is anatural complement of the use of ‘“‘grade”’ in the sense 
advocated in this essay. Gradation plains are then treated 
under four heads: sea plains, lake plains, stream plains, and 
flood plains. Of the first class it is said : 
Whenever in any region the process of slow upheaval comes to an end, 
and such district is still subject to degradation by rains and streams, the pro- 
cess of reduction goes on until the surface is brought down to the level of the 
sea... . Thesea-level plain is permanent in the absence of diastrophism. 
. . . Low lands with surfaces more inclined, and with more swiftly running 
streams, are still called AlZazzs though they are not fully brought down to 
baselevel ; sometimes they are, called Jeneplains (1895, 34, 35): 
Sea plain has not come into general use, perhaps because 
of possible confusion with sea-cut plains, or plains of marine 
denudation. The following extract gives an example of the 
