Studies for Students. 



PROPOSED GENETIC CLASSIFICATION OF PLEISTO- 

 CENE GLACIAL FORMATIONS. 



Pleistocene formations that are not either directly or indi- 

 rectly of glacial origin are not embraced in the classification 

 herewith proposed. 



There are at least three appropriate modes of classification of 

 the Pleistocene glacial formations : 



( i ) . A classification based upon the structural characteristics 

 of the deposits. 



(2). A classification based upon the origin of the formations. 



(3). A classification based upon the time relations of the 

 deposits. 



Only the second will be here considered. A purely struc- 

 tural classification has an indispensable value, and is a fit subject 

 for more and more critical consideration as our knowledge of 

 the glacial formations increases. The classifications of the past 

 will doubtless continue to need extension and more precise def- 

 inition as glaciology advances. Nevertheless, our structural 

 classifications do not seem to be so lacking in exhaustiveness, 

 nor so defective in discrimination as our genetic classifications, and 

 as time will not permit an adequate treatment of the three forms 

 of classification, it has seemed best to pass the first by with a 

 mere mention. 



A chronological classification of the Pleistocene formations 

 possesses the highest interest and constitutes one of the two 

 great goals sought by glaciology. One of these is to ascertain 

 how the formations were produced, the other, the times and 

 sequences of their production. But it is too early yet to fix upon 

 a satisfactory chronological classification. The data are not yet 

 sufficiently gathered nor have they been tested with sufficient 



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