60 THE JOURNAL OF GEOLOGY. 



The amount of englacial till under this view is little more 

 than that which was lodged in the body of the ice in its passage 

 over the knobs and ridges of the hilly and semi -mountainous 

 regions of the north. To this is perhaps to be added occasional 

 derivatives from the more abrupt prominences of the paleozoic 

 region and the superficial dust blown upon the ice from the 

 surrounding land, which was probably the chief source of the 

 silty material intermingled with the superficial boulders. The 

 total amount is thus quite small, though important in its sig- 

 nificance 



The eskers and kames of the region are made up of deriva- 

 tives from the basal material as shown by ( i ) the local origin of 

 the material in large part, (2) the mechanical origin of the 

 sands and silts, (3) the not infrequent glacial markings of the 

 pebbles and boulders, and (4) the disturbed stratification of the 

 beds.' If I am correct in respect to the kind and amount of 

 the englacial and superglacial material, it is obvious that eskers 

 and kames, such as are found in the interior, could not be derived 

 from englacial or superglacial sources. The term englacial as 

 here used does not include such materials as may be lodged in 

 the basal stratum of the ice and brought down to the actual 

 bottom by basal melting. 



The conclusions drawn from the phenomena of the plains 

 of the interior are not necessarily applicable to more hilly or 

 mountainous regions, 



T. C. Chamberlin. 



' See " Hillocks of Angular Gravel and Disturbed Stratification," Am. Jour. Sci. 

 Vol. XXVII., May 1884, pp. 378-390. 



