458 



SCIENCE. 



[N. S. Vol. XVIII. No. 458. 



that geographers will continue to study, so 

 far as they logically can, the relationship 

 of plants, animals and mankind to the 

 solid framework of the globe on which they 

 live, we must draw the line at the inven- 

 tion of new geological hypotheses to ex- 

 plain geographic difficulties on no better 

 evidence than that furnished by the diffi- 

 culties themselves; on the other hand, we 

 must insist that each new geological prin- 

 ciple must take its place amongst geo- 

 graphic explanations as soon as it is freely 

 admitted to be based on a sound substratum 

 of fact. 



I must confine myself to a few instances 

 of what I mean. Mr. Marr's geological 

 work on the origin of lake basins has led 

 to some remarkable and unexpected con- 

 clusions with regard to the history and 

 origin of the drainage of the lake district. 

 Some of the very difficult questions raised 

 by the physical geography of the North 

 Riding of Yorkshire have received a new 

 explanation from the researches of Pro- 

 fessor Kendall and Mr. Dwerryhouse, an 

 explanation which is the outcome of purely 

 geological methods of observation of geo- 

 logical materials. Again, the simple geo- 

 logical interpretation of a well-known 

 unconformity between Archtean and Trias- 

 sic rocks has made it extremely probable 

 that many of the present landscapes, not 

 only in the Midlands but elsewhere,, may 

 be really fossil landscapes, of great an- 

 tiquity and due to causes quite diiferent 

 from those in operation there at the present 

 day. In mountain regions, too, it can only 

 be by geological observation that we shall 

 ever determine what has been the precise 

 direct share of earth movement in the pro- 

 duction of surface relief. Such examples 

 .seem to indicate that many of the prin- 

 ciples must be of geological origin but of 

 geographic application. 



While geology has been of direct scien- 



tific utility in topography and geography, 

 there is another domain, that of economic 

 geology, which is entirely its own. The 

 application of geology extends to every 

 industry and occupation which has to do 

 with our connection with the earth on 

 which we live. Agriculture, engineering, 

 the obtaining of the useful and precious 

 metals, chemical substances, building ma- 

 terials, and road metals, sanitary science, 

 the winning and working of coal, iron, 

 oil, gas and water, all these and many more 

 pursuits, are carried on the better if 

 founded on a knowledge of the structure 

 of the earth's crust. Indeed a geological 

 map of this country, showing rocks, solid 

 and superficial, of which no economic use 

 could be made, would be nearly blank. Yet 

 so much has this side of the science been 

 neglected of recent years that our onl3' 

 comprehensive text-books on it are alto- 

 gether out of date. 



But in teaching geology as a technical 

 science, or rather as one with technological 

 applications, one of the greatest difficulties 

 before us is to steer between two opposing 

 schools, the so-called theoretical school and 

 the practical school. 



There are those who say that there is 

 but one geology, the theoretical, and that 

 a thorough knowledge of this must be 

 obtained by all those who intend to apply 

 the science. Others think that this is too 

 much to ask— that the time available is not 

 sufficient— and that it is only necessary to 

 teach so much of the subject as is obviously 

 germane to the question in hand. 



The best course appears to me to be the 

 middle one between the two extremes. If 

 the engineer or miner, the water-finder or 

 quariyman, has no knowledge of principles, 

 biit only of such facts as appear to be re- 

 quired in the present position of his pro- 

 fession, he will be incapable of making any 

 improvement in his methods so far as they 



