548 GEOLOGY 



areas, such as counties or townships; for so numerous are the facts 

 of the science that it requires a volume to discuss in detail even a 

 small area. For instance, to give the geology of a township with 

 sufficient fullness to make clear the earth-story there illustrated may 

 require a good-sized volume. 



We have seen that geology rests upon physics and chemistry as 

 its foundation; that it is closely related upon one side to astronomy, 

 upon another side to botany; that in its broader sense it includes 

 mineralogy; and that for its satisfactory development the aid of the 

 higher mathematics is needed. It is evident that the man who is to 

 advance geology must be broadly trained in science, and have a firm 

 grip upon the nature of energy, ether, and matter, and their inter- 

 actions. 



It is my conviction that when geology is placed in order under 

 the principles of physics and chemistry the science will have passed 

 through a greater revolution than at any previous time in its history. 



