STRATIFIED DRIFT 953 



fore, at the time of its maximum advance, ice and water must 

 have coo[)eratcd to bring into existence considerable quantities 

 of stratified drift. 



The edge of the ice was probably ragged, as the ends of 

 glaciers are today, and as the waters issued from beneath it, they 

 must frequently have left considerable quantities of such debris 

 as they were carrying, against its irregular margin, and in its 

 reentrant angles and marginal crevasses. When the ice against 

 which this debris was first lodged melted, the marginal accumula- 

 tions of gravel and sand often assumed the form of kames, a type 

 of stratified drift which is well known. ^ A typicalkame is a hill, 

 hillock, or less commonly a short ridge of stratified drift ; but 

 several or many are often associated, giving rise to groups and 

 areas of kames. Kames are often associated with terminal mor- 

 aines, a relation which emphasizes the fact of their marginal 

 origin. 



So far as the superficial streams which flowed to the edge of 

 the ice carried debris, this was subject to deposition as the 

 streams descended from the ice. Such drift would tend to 

 increase the body of marginal stratified drift from subglacial 

 sources. 



Marginal accumulations of stratified drift, made by the coop- 

 eration of running water and ice, must have had their most exten- 

 sive development, other things being equal, where the margin of 

 the ice was longest in one position, and where the streams were 

 heavily loaded. The deposits made by water at the edge of the 

 ice differ from those of the next class — made beyond the edge 

 of the ice — in that they were influenced in their disposition and 

 present topography, by the presence of ice. 



' Until recently kames have not been discriminated from eskers, and in the older 

 literature the two are confused. Kames, as distinct from eskers, are defined and dis- 

 cussed in the following places, though the list is incomplete : 



Chamberlin, 3d Ann. Rep. U. S. Geol. Surv., p. 300 ; Am. Jour. Sci., Vol. XXVII, 

 p. 378; Compte-Rendu, 5th Session International Congress of Geologists, p. 187; 

 Journal of Geology, Vol. I, p. 255; Journal of Geology, Vol. II, p. 531. Gkikie, 

 "Great Ice Age," 3d Edition, chap. xv. Salisbury, Report of the State Geologist of 

 New Jersey for 1891, pp. 89-95; Ibid., 1892, pp. 41, 79. 



