50 REMARKS ON CLASSIFICATION. 



Of course, every degree of ski]) exists in the applications of any classifi- 

 cation, and many men, even with erroneous principles, succeed better than 

 others do who work with correct ones. In this, however, it is a question of 

 methods and not of men ; if it were the latter, then no discussion would be 

 possible, since the older and more experienced would always, and justly, 

 claim the right to have their views followed. Since it is a question of 

 science and methods, it is often true that some young and fresh observer 

 may, starting from the ground gained by others, push on a little way beyond 

 them ; this too, when he may not have a tithe of the ability of the others ; 

 and it is not to be taken as presumption, if he endeavors to hold and point 

 out the ground he thinks he has gained. 



The principles and methods employed herein were essentially enun- 

 ciated by me in 1879,* the chief changes being the greater extension of the 

 subject, owing to further investigations ; and these principles have been used 

 by myself and my students in papers published since. Owing to the con- 

 densed or abstract form of the first publication, it seems to have been but 

 little understood by lithologists working in the mineralogical method of rock 

 classification ; but it is hoped that the publications made since then, includ- 

 ing this, will make my meaning sufficiently clear. One thing is certain, that 

 unless a lithologist has had an extensive range of study of both the unal- 

 tered and altered forms of rocks, and seen their relations in the field, such 

 understanding will be difficult. Bearing upon this, it is to be pointed out 

 that, outside of the rocks from a few volcanoes in Europe, every rock that I 

 have seen from that country is altered, to a greater or less degree ; 1)ut the 

 European classifications are chiefly based on such altered rocks. Hence, a 

 mineralogical classification would naturally be adopted there, and will be 

 tenaciously held to. A lithologist who is dependent on the material that 

 Europe alone can furnish him, has not the means at his command of judging 

 accurately regarding the basis of much of my work, which has been founded 

 upon much fresher and less altered specimens than his. The most that I 

 can hope to do, however, is to call attention to, and point out, that which 

 seems a better way than the one at present followed. To perfectly express 

 the natural system of rocks requires a universal knowledge of them — a 

 knowledge that it is not given to any man to possess. 



No definite scheme of classification can be laid down in the beginning ; 

 it must result from the study of all available specimens, and be the best 



* Bull. Mus. Coiiip. Z'.ol., 1S70, V. 275-2S7. 



