496 SCIENCES OF THE EARTH 



arduous task, not only because of the opposition of inherited preju- 

 dices, but even more because of the inherent difficulty of the problem. 

 To think that processes such as those of to-day have done all the 

 work of the past is appalling; yet we are constrained to believe it. 

 Even as waves, beaten up in a stormy sea subside after the winds are 

 calmed, so the mountain waves or wrinkles of the earth's crust, grow- 

 ing as long as erogenic storms are at work, are in time calmed to plains ; 

 and this not by unusual processes, but by the patient weathering 

 and washing of scraps and grains. While these slow changes go on in 

 the extinction of mountain systems, the races of plants and animals 

 that originally gained possession of the lofty young mountains, that 

 grew up with them, so to speak, must either adjust themselves to the 

 changes in their surroundings, or migrate to other homes, or vanish, 

 all in due order through the flowing current of time. 



Nowhere is the orderliness of geological changes better attested 

 than in the forms of ridge and valley seen to-day in various examples, 

 young and old, of wasting mountain ranges themselves, and in the 

 systematic adjustment that is attained by the drainage-lines with 

 respect to the structures on which they work. Here indeed is cumula- 

 tive testimony for unif ormitarianism ; for nothing but the long per- 

 sistence of ordinary processes can account for these marvelous com- 

 monplaces. So wonderful is the organization of these land and water 

 forms in physiographic maturity and old age, so perfect is their 

 systematic interdependence, that one must grudge the monopoly of 

 the term organism for plants and animals, to the exclusion of well- 

 organized forms of land and water. By good fortune, evolution is 

 a term of broader meaning: we may share its use with the biologists; 

 and we are glad to replace the violent revolutions of our predecessors 

 with the quiet processes that evolution suggests. 



It is the assurance of orderly continuity that binds the past to the 

 present in the endless sequence of events, and shows us that geography 

 is only to-day's issue of a perpetual journal, whose complete files con- 

 stitute geology. He must be a geographer of the old school who would 

 now maintain that his subject, in content and treatment, really be- 

 longs outside of the geological curriculum. It may, on the other 

 hand, be justly contended that the whole of earth-science is made up 

 of geographic sheets, until to-day, paleogeographic, if you like, 

 all horizontally stratified with respect to the vertical time-line. In 

 every sheet we find news of the relation of earth and life, of environ- 

 ing control and organic response, of physiography and ontography. 

 Every little item of news here published is worthy of close attention. 

 The reader may examine all sorts of items on a single sheet and con- 

 sider their temporary, areal distribution, and so acquire the geographic 

 view; or he may examine the changing items of certain areas, follow- 

 ing their chronological sequence in successive sheets, and so acquire 



