Editorial Comment. 1"'.> 
relationship with the Kansan. Aftonian, and [owan Btages of the 
Glacial period in the upper and more northern -part of the Mississippi 
basin. 
Some Stages of Apjxtlachian Erosion. Arthur Keith, Washington, 
I ). ( '. This paper gave a general review of the drainage systems of the 
Appalachian area, and of the agencies which contributed todevelop the 
present topography. It especially described the typical forms of erosion 
in that region and the grouping of the more and the less matured forms 
in relation to the main divides of the river systems, thus defining the 
normal sequence of degradation forms. 
The Tennessee river system was analyzed, and four main stages of 
reduction to baselevel were described, each peneplain being lower and 
smaller than the preceding, and each nearly level in the main valleys 
and gradually rising toward their peripheries. As each stream and 
branch diminishes, the forms of erosion rise in a concave curve through 
baseleveled plain, peneplain, valley, ten-ace. bottomland, planation 
slope, and gorge, to the residual mass. The omnipresence of this relation 
defines it as the law. and the uniformity of level in each well developed 
peneplain is its characteristic present feature. 
Similar features were cited as characterizing other river basins, so 
that the number of distinct stages of erosion is at least seven. 
Attention was called to the warping of peneplains in certain regions, 
and to its comparative rarity and localization as furnishing the excep 
tion to the usual uniformity of" level. Certain peneplains, described bj 
other authors as deformed or, warped, were found to he not deformed 
hut following the sequence of erosion forms and the normal slopes, even 
in a direction contrary to their theory, Their error was ascribed to the 
correlation of portions of different peneplains into one surface. Two 
peneplains with stronglj warped surfaces thus were made to appear in 
stead of four or more whose surfaces are only locally warped. 
EDITORIAL COMMENT 
Tin: James Hall Medals. 
The man of science whose accomplishments have received 
substantia] recognition from various dignitaries and learned 
bodies of the world is seldom a roused to the fad that while 
the honor achieved is his the possibility of attaining il may 
have rested with others. Hence it is that due acknowledg 
incut of cooperation in such achievements is still a matter id' 
gratified, il' surprised, comment. Not every such highly dis 
tinguished man can. even if lie would, turn to his advisers 
and supporters with substantia] public recognition of such 
contributory obligation; such avowals, even when possible, 
are too frequently altogether withheld, involving no added 
