EXPLANATORY TREATMENT OF LAND FORMS 103 



past time. Again, when we say "volcano" we mean the product of certain 

 processes acting through a certain measure of time, as a result of which 

 the thing produced has certain peculiarities of composition, structure, and 

 form. Similarly, when we say "peneplain" we imply, in the mere men- 

 tion of the term, the action of normal erosive processes on structures of 

 any kind for a vast period of time, as well the land surface of small relief 

 which the erosive processes have produced and which transects the under- 

 ground structures indifferently. Structure and process are thus seen to 

 be involved in the meaning of several familiar geographical terms in 

 essentially the same manner that they are involved in more elaborate ex- 

 planatory descriptions, such as that quoted for the Front Range. It 

 would be absurd to regard the terms delta, volcano, and peneplain as 

 geological instead of as geographical terms ; hence it can not be reasonable 

 to regard the description of the Front Range as geological instead of 

 geographical. 



TECHNICAL EXPLANATORY TREATMENT OF LAND FORMS 



On the other hand, the description of the Front Range is not a good 

 sample of elementary geography, nor of empirical geography, nor of full- 

 fledged geography. The description was intentionally phrased to give an 

 example of explanatory treatment as contracted with empirical treat- 

 ment; of advanced grade and of technical style as contrasted with ele- 

 mentary grade and popular style; of condensed form instead of detailed 

 form, and it was intentionally restricted to one subdivision of the inor- 

 ganic or physiographic side of geography, namely, to that subdivision 

 which is concerned with land forms; all other inorganic subdivisions, 

 such as oceanic problems or climatic conditions, as well as all of the other 

 side of geography, namely, its ontographic relations — the relations into 

 which vegetable, animal, and human inhabitants enter with their inor- 

 ganic environment — were intentionally omitted. The description being 

 of advanced grade, it may well be impenetrable to juvenile geographers, 

 but it is not thereby transferred to geology. Its advanced plirasing neces- 

 sarily requires on the part of those for whom it was written a familiarity 

 with various rocks, structures, and processes, so that a brief mention 

 shall lead to an easy understanding of the landscape in which they result. 

 Being of explanatory treatment, it may seem unfamiliar to empirical 

 geographers, who vainly wish to limit- their study to the earth's present 

 surface, and who think that they have nothing to do with underground 

 rock structure and past processes ; but the description is not tliereby lost 

 to geography. Being condensed in form, its understanding may demand 

 close attention if it is spoken or repeated reading if it is printed, for all 



