5 1 8 THE JOURNAL OF GEOLOGY. 



severity, to admit of satisfactory correlation of the successive 

 glacial stages even within the limits of a single province. How 

 much less, then, those of different continents. While recognizing, 

 therefore, the supreme interest that attaches to a chronological 

 classification, I am impressed with the feeling that it is best to 

 postpone a formal attempt to establish such a classification until 

 the data shall be more adequately developed. It is believed 

 that the development of a more satisfactory genetic classification 

 will be a step toward a more satisfactory chronological classifica- 

 tion. 



The following outline is submitted for discussion : 



Six general classes are proposed. 



A. GENERAL CLASSES. 



I . Formations produced by the direct action of Pleistocene glaciers . — 

 As very much of that which is commonly embraced, for conven- 

 ience, under the general phrase glacial formations is not the direct 

 and simple product of glaciers, but springs in part or in whole from 

 accessory agencies, it is thought serviceable to discriminate the 

 simple from the complex formations. In this classification 

 glaciers are assumed to be the primary and chief agency in the 

 production of the formations classified, but the secondary and 

 associated agencies are very important, and often the final 

 expression of the deposits is due chiefly, and sometimes wholly, 

 to these auxiliary agencies. 



II. Formations produced by the combined action of Pleistoce7ie 

 glaciets and accompanying glacial drainage. — All of the ice of the 

 glaciers except that portion which was transformed into vapor 

 passed away in the form of glacial waters, and to this there was 

 added the rain precipitated upon the glacial expanse. The com- 

 bination of the work of this large volume of water with that of 

 the ice gave rise to results which neither the ice alone nor the 

 water alone could accomplish. These constitute a distinct class 

 of deposits. 



III. Formations produced by glacial zvaters after their issuance 

 from Pleistocene glaciers. — While the glacial waters were acting 



