1885.] NATURAL SCIENCES OF PHILADELPHIA. 161 



associated with terminal moraines in Wisconsin and elsewhere, 

 and his paper contains a good reference list to the literature of 

 kames. The kames described by him differ from those described 

 in the present paper in being knob-like hills, "simple isolated 

 mounds," or clusters of such mounds, rather than linear ridges, 

 and also in lying transverse to the glacial movement, which is 

 not the case with the Pennsylvania deposits. 



Origin of Kames. — The early view of geologists as to the 

 origin of kames, was that they were washed into shape by the 

 waves and currents of the ocean. This was the view held by Dr. 

 Jas. Geikie in the first edition of his " Great Ice Age," l and was 

 formerly advocated by many geologists both in Europe and 

 America. But recent researches have shown that this view is 

 untenable, and in the second edition of Dr. Geikie's book kames 

 are regarded as the work of subglacial rivers. 2 



The researches of American geologists, especially the work in 

 New England of Upham, Wright and Stone, have shown the 

 occurrence of kames in positions out of the reach of oceanic 

 currents. When marine deposits occur, as they do along the 

 border of New England, in the St. Lawrence Valley, and else- 

 where, they are seen to be horizontally stratified sands and clays 

 often holding marine fossils, and clearly overlying the kame 

 ridges. The terrace material of flooded rivers is also observed 

 to overlie the kames. 



On the other hand, kames are newer than glacial till, and 

 overlie and swing around the drumlins of Massachusetts. These 

 " drumlins," like those described by Kinahan and Close in 

 Ireland, 3 are low oval hills, composed of unstratified glacial till, 

 and are most satisfactorily explained as lenticular ground moraines 

 formed under the ice sheet during its advance. They have been 

 called " lenticular hills." Their longer diameter is generally 

 parallel to the direction of the ice flow, as shown by neighboring 

 stria?, and they appear to be of a mid-glacial age. 4 



1 Page 229. 



2 Page 217, etc. 



3 Glaciation of Iar-Connaught, Kinahan and Close, 1872. 



4 For discussion of "lenticular hills," sec papers inProc. Bost. Soc. Nat. 

 Hist., by N. S. Shaler (xiii, 190), and by C. H. Hitchcock (xix, 63), and 

 Geol. Survey of N. H., iii, p. 287 ; also, an article by W. M. Davis, Science, 

 iv, 419. 



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