I 



1902,1 DAVIS — SYSTEMATIC GEOGRAPHY. 241 



of human events, even though he can make explicit mention of the 

 greater ones only. The physicist must bring the behavior of a 

 river in making its flood plains and of a stone in falling from a cliff 

 under the domain of physical law, although he may not make 

 mention of every flowing stream and of every falling stone in his 

 systematic text-book. The chemist must discover all the kinds of 

 changes in composition caused by the weathering of rocks; he 

 must learn the composition of everything from the miller to his 

 flour and his millstone. It is therefore not in terms of the things 

 studied that a science can be defined, but only in terms of the 

 relationships involved in the study. The things with which the 

 geographer is concerned may also concern the physicist, the chemist 

 and the historian ; but as far as these things enter into the relation 

 between the earth and its inhabitants, they constitute the content 

 of geography. 



It is particularly in relation to geology that geography has been 

 needlessly confused. Geology is essentially a historical study; it 

 is for the earth what history is for man. Geography, on the other 

 hand, is distinctly not a historical study; what is often called 

 historical geography might be much better called geographical 

 history. Geography considers the relationship of existing condi- 

 tions, inorganic and organic ; and as far as the dimension of time 

 enters into geographical methods, it is introduced not for the 

 purpose of studying the sequence of events that lead up to existing 

 phenomena — that belongs to geology or to history — but for the 

 purpose of better seeing the existing phenomena themselves, as will 

 be more fully shown below. Thus understood, geology and geog- 

 raphy are closely related ; it may be fairly said that geology cul- 

 minates in geography, and that all geology consists of a sequence 

 of paleogeographies. Surely, no geologist would dismiss the present 

 condition of the earth and its inhabitants from consideration as 

 constituting the last page in the recent chapter of historical geology. 

 Ocean navigation and cable laying, city growth and railroad build- 

 ing deserve a place in the geology of the recent period on exactly 

 the same ground that trilobite tracks and dinosaur prints belong in 

 the record of the past. Conversely, every geographer should con- 

 ceive all the geological history of the earth as involving a succession 

 of geographies, horizontally stratified with respect to a vertical time 

 line. All the processes of slow erosion, of volcanic eruption, of 

 rising and falling lands, of organic adaptations, formed elements of 



