GLACIAL PHENOMENA OF NORTH AMERICA. 67 



kames is that they mark the course of the floods which 

 must have characterized the last stages of the glacial 

 period (the Champlain Epoch). When but a few hun- 

 dred feet of the ice was left, the earthy material which had 

 been held in the whole mass must have rested in places 

 in a thick deposit upon the lower stratum of ice, and must 

 have been brought into lines of special depth through pre- 

 vious action of superficial currents of water. At this 

 time the remaining ice frequently obstructed the natural 

 outlets to the floods, so that they were to a considerable 

 extent independent of the present river channels, though 

 not of the larger valleys. The final result was, that when 

 the various ice barriers were removed and the water 

 sought its present lines of outflow, these previous gravel 

 deposits of the glacial rivers were left undisturbed, except 

 where the changed course of the water-flow led across 

 their path and eroded them. In places, doubtless, the 

 earthy material had been deposited in ice channels ; in 

 which case a ridge would be formed when the sides 

 melted away. In other places vast masses of ice would 

 have been so covered with sand and gravel that the melt- 

 ing would be greatly delayed. In such cases the earthy 

 material would settle down in a very irregular manner, 

 forming the characteristic reticulated ridges and the fre- 

 quent kettle holes where the material had slid off on every 

 side and left an enclosed mass of ice to melt away 

 gradually. 



Soon after beginning to investigate the kames, my at- 

 tention was directed by Mr. Clarence King to a terminal 

 moraine on Cape Cod and the Elizabeth Islands. His 

 communication to me Avas published in my paper before 

 the Proceedings of the Boston Society of Natural History, 

 for Dec, 187(3. Upon hearing of this Mr. Upham at 

 once visited the locality, and found that a terminal mo- 



