GEOLOGY IN SERVICE OF MAN WATTS 295 



of newly raised sediment were available for occupation, when the 

 ajirents of denudation and renewal were in vigorous operation, and 

 when a wave of rapid organic evolution was active. And a con- 

 jecture may be permitted that human evolution itself was probably 

 hastened by the latest climatal severity through which the earth 

 passed, the effects of which are only slowly passing away. 



Much of what has just been said may revive recollection of an 

 old Swiss guide book which praised the beneficence of Providence 

 in directing the dreaded avalanches " into the desolate and unin- 

 habited valley of the Trumleten Thai and in sheltering from them 

 the beautiful, fertile, and inhabited valley of Lauterbrunnen." 

 However, it is far from my intention to imply that " everything is 

 for the best in this best of all possible worlds," but only to point 

 cut in reviewing the long chain of events of which we see the 

 present end-product in civilized man, that within the ken of the 

 geologist there have been many critical stages in the earth's history 

 when any marked change in the conditions which then prevailed 

 must inevitably have reacted profoundly upon the development of 

 the human race when at long last it stepped out from the lower 

 ranks to take the earth as its rightful possession. 



CONCLUSION 



A review of the history and present position of geology shows 

 that its better-known services to mankind have been in relation to 

 the foundations on which industrial development and modern civili- 

 zation have been built — the mineral resources of the earth. These 

 are many and various, all of them explored by geological methods. 

 In every application of them we are again brought back to the 

 primal essentials — water, iron, and fuel — and it is in the discovery 

 and exploitation of these that the services of geology have been of 

 especial value. 



But in the course of the development of both the economic and 

 the scientific sides of geology the principles discovered and elabo- 

 rated have fertilized and enriched human thought as expressed, 

 not only in other sciences but also in the sphere of literature. As 

 it has become more precise and is able to give a more accurate and 

 detailed picture of the stages through which the earth passed dur- 

 ing the long stor}^ unfolded by the study of the stratified rocks, it 

 has shown that the earth, though only a minute fraction of the 

 visible universe, has had a wonderful and individual- history of its 

 own. The keynote of this history is evolution, the dream of phi- 

 losophers from the earliest times, now passed from the realm of 

 hypothesis into that of established theory. 



