162 PROCEEDINGS OF THE ACADEMY OF [1885. 



Kames, therefore, would appear to be intermediate in age 

 between the time of the deposition of the till or ground moraine 

 and the age of the terraces and marine deposits. Mr. Upham l 

 regards them as due to rivers flowing in channels formed upon 

 the surface of the ice near its retreating edge. As the wall of 

 ice on either side disappeared at the final melting of the ice sheet, 

 the gravel and sand remained in long ridges or in mounds. He 

 believes that kames were formed at or near the mouths of these 

 surface streams, extending along the valley as fast as the ice front 

 retreated. 



Prof. G. F. Wright 2 believes that in many cases they are due 

 to the sliding down from the surface of the ice of morainic debris 

 accumulated near its end, so that they may represent medial 

 moraines. He shows that they do not lie in channels worn in the 

 till, and that very often they are unstratified, and thinks that the 

 material composing them may have first formed lines upon the top 

 of the ice. But, as Prof. Stone has shown, it is only among the 

 highlands that the material of kames are poorly stratified ; as 

 soon as open valleys are reached the materials are worn, rounded 

 and stratified. 



Quite recently Prof. T. C. Chamberlin, of the U. S. Geological 

 Survey, in an important paper " On the Terminal Moraine of the 

 Second Glacial Epoch," 3 proposes to separate kames from "Asar," 

 regarding kames proper as tranverse to the slope of the surface, 

 the course of the valleys and the direction of the drift move- 

 ment," 4 while the term asar is employed to designate long river- 

 like ridges of gravel. Asar are described as extending " from 

 higher to lower levels, following in general but not in detail the 

 course of the greater valleys and the direction of glacial stria- 

 tion." As stated elsewhere, 5 the} r are held to be " the products 

 of the drainage system of practically extinct glaciers." 



This is practically the view of Professor Stone, and of other 

 recent workers in this field, as it is that of the present writer. 

 Moraines are the product of the advance of the ice-sheet, osars 



1 Geol. of N. II., vol. 3, pp. 14-176. 



2 Proc. Bost. Soc. Nat. Hist., xx, 219. 



3 Third An. Rep. U. S. Gcol. Surv., p. 295, etc. 



4 Loc. cit., p. 300. 



5 Amer. Jour. Sc., xxvii, 378. 



