Sa CHARLES R. KEVES 
lated by the geographers have to be made much more compre- 
hensive than they now are, before they can accomplish their 
intended service. To begin with, an adequate scheme should be 
based directly upon geological agencies. Topographic features 
are largely only the outward expressions of the internal arrange- 
ment of the earth. The two groups of characters should be 
paralleled. One represents form— the physiognomy ; the other 
structure—or anatomy. Yet some geographic features have no 
measurable equivalent in structure; and many structures do not 
give rise directly to distinctive forms of surface relief. 
In a strictly genetic arrangement, where the processes and 
not the products are made the central theme, the continual oper- 
ation of two antagonistic forces does not really exist. Construc- 
tive and destructive agencies can be recognized only when the 
phenomena are made the basis of the scheme. Processes are 
merely operative. If coupled with the products at alligam 
classification, all must be regarded as formative or constructive. 
The product’s destruction, its loss of identity, is wholly imma- 
terial’ The action of agencies is merely to produce constame 
change. 
A truly genetic scheme for the classification of natural phe 
nomena thus always has prominently presented its underlying 
principle of cause and effect. All products must find accurate 
expression in terms of the agencies. Only then are the broader 
distinctions in geological classification rendered possible. The 
various taxonomic groups are made separable only when it is 
recognizable how, or in what manner, the component parts of 
the materials dealt with are influenced. Under one set. of agen- 
cies and conditions a rock-mass is affected in one way, and the 
component units act altogether differently from what they do 
under another set of agencies. The primary groupings of the 
geological processes must be based, therefore, upon the manner 
in which these agencies affect the rock materials. 
When rocks, or the materials with which geology has to 
deal, and through the medium of which geological phenomena 
take definite form, are carefully considered with reference to 
