6i4 CHARLES R. VAN HISE 



one continent; but no man can know more than an inappreciable 

 portion of the geological facts of even the countries which have been 

 somewhat closely studied; and these countries comprise but a small 

 part of the earth. 



But it is unnecessary for a man to know all the facts of geology. 

 He need only know the more important facts for a sufficiently broad 

 region so that he may understand the recognized principles of the 

 science, assist in their development, and take part in the discovery 

 of new principles. The discoveries will be found to be largely 

 applicable to the vastly greater regions of the world which are not 

 considered by the discoverer. All this is very fortunate for the 

 science of geology. A student beginning the subject may fully com- 

 prehend the truthfulness of many principles which have been devel- 

 oped in various parts of the world through the illustrations furnished 

 by his native parish. 



From the foregoing it appears that the geology of the future is 

 to have two aspects, which, as time goes on, will become more and 

 more clearly differentiated: first, the principles of geology; second, 

 the application of principles to various parts of the world. 



CONCLUSION. 



It is clear that the evolution of the science of geology has followed 

 a strictly natural course. Before the subject was recognized as a 

 science, the earth was being observed. When man turned to nature- 

 study, he began to observe the phenomena exhibited by the earth, 

 such as the stratification of the rocks, and the presence in them of 

 objects which are called fossils. After such observations were made, 

 it was inevitable that sooner or later the question should arise as to 

 the manner in which the results observed were accomplished. Thus 

 the observation of phenomena led to a study of processes. Sands 

 like those observed in a consolidated form were seen in the process 

 of building. The conclusion followed that the consolidated strati- 

 fied rocks were formed by the processes observed upon the seashore. 

 Sea shells were seen to be produced by animals and to be deposited 

 with the upbuilding sands. This led to the explanation that the 

 fossils in the sedimentary rocks were due to the processes observed. 



After a large number of explanations, the methods of which were 

 the same as in the illustrations given, the general doctrine was evolved 



