8 PROCEEDINGS OF SPRINGFIELD MEETING. 



The first paper read was — 



BEARING OF PHYSIOGRAPHY ON UNIFORMITARIANISM 

 BY W. M. DAVIS 



[^Ahstract\ 



It is desirable to open tliis brief paper with a definition of physiography and 

 geograph}^, the latter being the study of the earth in relation to man, the former 

 being such study of the earth as is necessary in order to understand its relations 

 to man. One of the important divisions of physiography concerns itself with the 

 study of the lands ; and in order to appreciate the existing facts of land form, their 

 development is carefully considered. This division of the subject covers geomor- 

 phology and geoniorphogeny of some authors, the genetic considerations being in- 

 cluded under physiography, not for their own sake, but for the light that they 

 throw on land morphology. For example, in attempting to understand the geo- 

 graphical conditions of Pennsylvania, including therein the distribution of popu- 

 lation, products and industries in their relation to the features of land form, it is 

 essential that both classes of facts should be accurately known ; and it is the duty 

 of physiography to supply a fitting- account of the second class of facts. 



An absolute, em|)irical descrii)tion of the land forms is unsatisfactory ; it is arbi- 

 trary in arrangement, unsympathetic with the real life of the forms concerned and 

 generally very unsuccessful in its effort to see the facts that are to be described. 

 For these reasons a descrii)tion based upon natural genetic conditions is to be pre- 

 ferred ; it is rational in arrangement, thoroughly sympathetic with the real life of 

 the land and most aidful in bringing to sight and mind the cliaracteristic elements 

 of form ; it enlivens physiography much in the same way that the principle of 

 evolution has enlivened botany and zoology. It thus becomes the duty of the 

 physiographer to acquaint himself with the develoj^ment of land features, not 

 merely that he should understand the process and sequence of development, but 

 chiefly so that he shall better perceive the products of development. The land 

 chapter of physiography might therefore be defined as the study of the earth in 

 relation to its surface forms, including tlie arrangement and character of the ele- 

 ments of form. Knowing that existing forms are dependent on antecedent condi- 

 tions, physiography might be defined, following Mackinder, as the ''study of the 

 present in the light of the past." The results of this study furnish us a knowledge 

 of the earth with which we enter geography. 



Geology is the study of the earth in relation to time. The guiding principle in 

 this study is that present processes are the best guides to the understanding of past 

 processes, this being the teaching of Hutton and the British school in general. 

 Geology may therefore be defined, again following Mackinder, as the "study of the 

 past in the light of the present." Uniformitarianism, reasonably understood, is 

 not a rigid limitation of past processes to the rates of present processes, but a 

 rational association of observed effects with competent causes. Events may have 

 progressed both faster and slower in the past than during the brief interval which 

 we call the present, but the past and present events differ in degree and not in 

 kind. This rather elastic understanding of uniformitarianism seems to me com- 

 paratively safe from the objections that have been urged against the more rigid 

 conception that some authors regard as necessarily intended in the writings of 



