GEOLOGICAL NATURE OF GEOGRAPHICAL STUDIES ill 



and of mixed geographical descriptions, and let them measure the strictly 

 geographical value of their descriptions by giving a single-minded atten- 

 tion to their success in providing strictly geographical pictures. Natu- 

 rally if a purely geographical description, from which geological terms 

 are absent, is read by a geologist who wishes to know the names of rock 

 formations he will find it unsatisfactory ; but it is not for the purpose of 

 giving satisfaction to a geologist that geographical descriptions are pre- 

 pared. If, on the other hand, a geographer maintains that he as a geog- 

 rapher gains satisfaction from the mention of a geological formation by 

 its technical date-name, let him try to specify exactly the way in which 

 such mention gives him geographical satisfaction and he will find much 

 difficulty in doing so. Let it, however, be clearly understood that if any 

 writer, be he geographer or geologist, wishes to add to a geographical 

 description supplementary information on any subject, such as the names 

 of geological formations, a rule for the extraction of cube roots, or advice 

 on the use of Latin subjunctives, he is, of course, perfectly free to do so ; 

 but do not let him think that in so doing he is making himself or his 

 description more geographical. 



The nature of a truly geographical description of explanatory style 

 may be emphasized by pointing out the nature of a proper geological de- 

 scription. In a geological description each fact of existing structure 

 serves, explicitly or implicitly, as a basis for inferences regarding past 

 conditions and processes of deposition, deformation, intrusion, denuda- 

 tion, or other process, and each inference as to the conditions and proc- 

 esses of past time should be referred to its proper place in time-sequence 

 in order to give due emphasis to the essentially historical aspect of 

 geological science. Between this sort of a description and a properly 

 geographical description there are abundant contrasts. 



THE GEOLOGICAL NATURE OF CERTAIN GEOGRAPHICAL STUDIES 



There are, however, articles of a certain kind, often written by geogra- 

 phers and published in geographical journals, and therefore commonly 

 associated with geography, which more logically belong with geology. 

 These are articles which are concerned with the past action of various 

 processes in producing different kinds of land forms, and in which the 

 manner of action of the processes and the nature of the forms that they 

 produce is still under discussion, because the processes have not in this 

 respect been fully investigated by those scientists who concern themselves 

 chiefly with the operations of past time. A hundred years ago the dis- 

 puted action of rivers in carving valleys occupied many pages of this 

 kind ; today the disputed action of glaciers in modifying land forms pro- 



