EARTH SCIENCES IN NINETEENTH CENTURY 68l 



It is true that geology has so largely to do with past time that it 

 is not popularly understood to include the present; but it cer- 

 tainly does include the present, and the future also, as fast as it 

 arrives. There is no possibility, in the understanding that we have 

 now gained of earth science, of stopping the geological record at any 

 stage of the Pleistocene, and calling the rest "geography;" that would 

 involve the resurrection of buried theories, which held the past to be 

 unlike the present order of things. 



Conversely, geography is stultified when absolutely limited to 

 the things of today, as if the things of the past were of another nature. 

 It is of course popularly so considered, and perhaps for that reason its 

 scientific development is stunted. When regarded objectively, the 

 geography of today is nothing more nor less than a thin section at the 

 top of geology, cut across the grain of time; and all the other thin 

 sections are so much more like the geography of today than they are 

 Hke anything else, that to call them by another name — except perhaps 

 " paleogeography " — would be adding confusion to the earth's past 

 history instead of bringing order out of it. Our plain duty here is to 

 emphasize the continuity of events, that great result of our studies, 

 and not to imply a break in their succession by using unlike terms for 

 different members of a single series. 



Geology thus being composed of a succession of countless geogra- 

 phies, geography, in its widest sense, is likewise composite, including 

 its inorganic and its organic parts. It is particularly concerned 

 with the surface of the earth today, as the home of life; but "surface" 

 and "today" must here be very freely construed; for we must draw 

 upon the sub- and super-surface parts, and on the days before today, 

 whenever we find profit in so doing. When we study the shape and 

 size of the earth, we touch upon what may be developed into geodesy. 

 When we study the inorganic parts of the earth for themselves, in 

 what may be called their static relations, we enter upon mineralogy and 

 petrology, or geochemistry; for it must be remembered that water 

 is a mineral and that air is a rock. When we study the dynamic 

 relations of the inorganic parts of the earth, we have geophysics, 

 within which oceanography and meteorology are subdivisions, of 

 rank similar to terrestrial magnetism and to that large category of 

 phenomena that includes the activities of the earth's crust. It is true 



