LIMITATION OF USE OF GEOLOGICAL ELEMENTS 109 



It may be fairly asserted that practically every trained geographer, who 

 has in recent years acquired a good understanding of both the ejnpirical 

 and the explanatory kinds of mental equipment and who has made a 

 faithful comparison of their efficiency in the description of actual land- 

 scapes, has decided in favor of the explanatory equipment. Explanatory 

 description is rapidly gaining^ acceptance wherever it is understood. 

 Geographers of the older school still, naturally enough, prefer the em- 

 pirical methods in which they were originally trained; yet even they use 

 certain explanatory terms, such as sea-cliff, moraine, and many others, in 

 a semi-conscious way; but they do not intentionally and whole-heartedly 

 adopt the principle of explanatory description and carry it systematically 

 forward to its full application. On the other hand, the most pronounced 

 rationalist will not infrequently meet a feature of a landscape for which 

 he can not provide a safe explanatory counterpart because he is not fully 

 assured that he understands its origin. In such a case he may say, *^It 

 looks as if it were so and so. In using such a qualifying phrase he 

 frankly presents his best attempt at an explanatory description, and at 

 the same time shows that he is in doubt about its correctness. He may 

 indeed not infrequently encounter features for which he has no satisfac- 

 tory explanation at all; he must then with equal frankness fall back on 

 an empirical description, but always with expressed discontent; always 

 with the hope and the effort to find the origin of the form and then to 

 give it a properly explanatory description. 



LIMITATION OF GEOLOGICAL ELEMENTS IN GEOGRAPHICAL DESCRIPTIONS 



Let me in returning more particularly to land forms note again that 

 what is here called the explanatory description of a landscape includes, as 

 has been stated already, simply so many of the inferred facts of past time 

 as bear helpfully on the understanding and description of the observed 

 facts of present time. If this still savors of geology it may be urged that 

 all ground for classing such a treatment under geology instead of under 

 geography is withdrawn when the words "and no more" are added, thus - 

 "The explanatory description of a landscape includes simply so many^ 

 and no more of the inferred facts of past time as bear helpfully on the 

 understanding and description of the observed facts of the present time." 

 There is, of course, no break in the backward stretch of the chain of 

 causation from the geographical present into the geological past, but 

 there is a limit soon reached as to the number of back-reaching links in 

 the endless chain which are practically helpful in the description of exist- 

 ing forms — that is, helpful in forming mental counterparts of existing 

 forms. German geographers are, in my judgment, inclined to introduce 



