94 W. M. DAVIS RELATION OF GEOGRAPHY TO GEOLOGY 



method of describing the forms of the lands. In illustration of the prin- 

 ciples that seemed to me most important I introduced a brief and tech- 

 nical geographical description of the land forms seen in the Front Eange 

 of the Rocky Mountains in central Colorado during an excursion in the 

 summer of 1910, regarding which a fuller account is about to be published 

 in the Annals of the Association of American Geographers; yet at the 

 close of the meeting the feeling prevalent among some of the geologists 

 present seemed to be that my description did not belong under geography, 

 but under geology. The description had seemed to me to belong under 

 geography, and to be indeed as good a piece of geography, in so far as 

 land forms enter into geography, as I could make, because its object was 

 the description of the existing landscape. Yet, in the opinion of geologic- 

 ally competent listeners, what I had said was not geography; it was 

 geology. * Evidently, then, the relations of these two sciences are not fully 

 agreed on. I therefore propose to devote this address to the "Eelation of 

 Geography to Geology," with special relation to the forms of the lands, in 

 the hope of showing at least my own grounds for regarding as geography 

 what other members of our Society may consider to be essentially geology. 

 The address is divided into four parts. The first discusses the use of 

 explanatory geological matter as a means to a geographical end; the 

 second shows the necessity of explanatory treatment in modern geog- 

 raphy; the third proposes a device by which the presence of geological 

 matter in geographical descriptions is made inconspicuous, and the fourth 

 turns more particularly to the general topic of the address, the relation 

 of geography to geology. 



Part I. The Use of explanatory geological Matter as a Means 



TO A GEOGRAPHICAL EnD 

 AN EXPLANATORY DESCRIPTION OF THE COLORADO FRONT RANGE 



The brief and technical description of the Front Eange, the systematic 

 place of which in the two sciences appeared last winter to be in doubt, 

 was, as nearly as I can now reproduce it, as follows : 



The Front Eange of the Eocky Mountains in central Colorado, north- 

 west of Denver, is a highland of disordered and generally resistant crys- 

 talline rocks, which show signs of having been long ago worn down from 

 its initially greater mass to a surface of faint relief, slowly depressed and 

 more or less broadly buried under a heavy cover of sedimentary strata. 

 Then, as the result of a widespread uplift, a part of the compound mass 

 west of a pronounced monoclinal displacement along a north-south line, 

 came to stand above the rest, and thus the highland province of the mouu- 



