﻿494 8. V. Wood, Jim. — American mid British Surface- Oeology. 



of the Highlands the Drift was entirely of Kame character, i.e. 

 gravel with boulders, though Boulder-earth covers the mountain 

 sides up to great elevations. Assuming, therefore, that the north of 

 Britain rose from its limited submergence during the Hessle period, 

 and before the glaciers occupying the valleys of the m.ountain 

 districts had wholly melted back, and then, after its elevation, that 

 this melting back took place subaeriallj'', we seem to me to get an 

 explanation of much of the complex and seemingly conflicting 

 phenomena of that region ; for in the higher valleys which the 

 limited post-Grlacial submergence was insufficient to bring down to 

 the sea-level, the valley drift would be all of this character, while 

 in the lower valleys, especially towards their seaward terminations, 

 the lower part of the Drift would be principally unwashed, moraine, 

 and the upper part of it washed Kame gravel. 



Applying this now to the case of Ohio, and assuming, for the 

 reasons given previously, that no depression of that part of the con- 

 tinent took place until after the growth of the forest-surface (2), 

 which rests on the Erie clay, it appears to me that when the ice-sheet 

 to which Prof. Newberry attributes the Ei'ie clay reached to and 

 rested on the water-parting between the St. Lawrence and 

 Mississippi basins, where these Esker and Kame gravels are found, 

 and where the grooved rock-surface attests the former presence of 

 the glacier-sheet, its dissolution was all subaerial ; and the water 

 resulting from it escaped into the Mississippi valley, so that the 

 resulting moraine was washed out into Karnes and Eskers ; but 

 that so soon as it wasted back from the water-parting, and into the 

 St. Lawrence basin, the melting of the ice began to form a lake, and 

 this washing out of the moraine ceased. The moraine then extruded, 

 being all left subaqueously, retained its original unwashed form of 

 Glacial (Erie) clay, similar in character to the Upper Glacial clay of 

 England, which was left beneath the sea by the retreat of the ice- 

 sheet during the general submergence of Britain. If this view be 

 sound, the age of the Ohio Karnes and Eskers which, following the 

 sequence assigned to them by Prof. Newberry, 1 have called 3&, 

 would really be that of the oldest portion of the Ohio Glacial series, 

 viz. coeval with the Erie clay (No. 1), of which they would con- 

 stitute in the horizontal sequence of Glacial deposits the earliest 

 portion.^ 



The occupation of the Canadian highlands by an ice-sheet sub- 

 sequently to the growth of the forest over the Erie clay seems to me 

 to conspire with the evidence afforded by the recent character of 

 the mollusca of the Leda, Champlain, and other marine clays of the 

 lower basin of the St. Lawrence, and Atlantic coast, to show that 



1 Prof. Newberry observes that only patches of the Erie clay occur on the water- 

 parting which is the region of these Karnes, and in the details of sections that he 

 gives, these Kame gravels do not rest on the Glacial deposits, hut on the rock- surface. 

 Mr. Geikie, in the second edition of his " Great Ice Age," similarly suggests that 

 the Ohio Karnes were due to the action of water flowing from the glacier-ice when 

 it reached to the centre of Ohio, but he does not of course recognize such a distinc- 

 tion as I have endeavoured to draw between the deposit formed by the subaerial 

 extrusion of the moraine and that formed by its subaqueous extrusion. 



