494 S. V. Wood,jun. — American and British Surf ace- Geolog y. 
of tke Highlands tke Drift was entirely of Käme ckaracter, i.e. 
gravel with boulders, though Boulder-earth covers the mountain 
sides up to great elevations. Assuming, therefore, that tke nortk of 
Britain rose frorn its limited submergence during tke Hessle period, 
and before the glaciers occupying tke valleys of tke mountain 
districts had wkolly melted back, and tken, after its elevation, tkat 
tkis melting back took place suhaerially, we seem to me to get an 
explanation of muck of tke complex and seemingly conflicting 
pkenomena of tkat region ; for in tke kigker valleys wkick tke 
limited post-Glacial submergence was insufficient to bring down to 
tke sea-level, the valley drift would be all of tkis ckaracter, while 
in tke lower valleys, especially towards tkeir seaward terminations, 
tke lower part of the Drift would be principally unwasked moraine, 
and tke upper part of it washed Karne gravel. 
Applying tkis now to the case of Okio, and assuming, for tke 
reasons given previously, tkat no depression of tkat part of tke con- 
tinent took place until after tke growtk of tke forest-surface (2), 
wkick rests on the Erie clay, it appears to me tkat wken tke ice-sheet 
to wkick Prof. Newherry attributes the Erie clay reached to and 
rested on the water-parting between tke St. Lawrence and 
Mississippi basins, where these Esker and Käme gravels are found, 
and wkere tke grooved rock-surface attests tke former presence of 
tke glacier-sheet, its dissolution was all subaerial ; and tke water 
resulting from it escaped into tke Mississippi valley, so that the 
resulting moraine was wasked out into Karnes and Eskers ; but 
tkat so soon as it wasted back from the water-parting, and into the 
St. Lawrence basin, tke melting of tke ice began to form a lake, and 
tkis wasking out of tke moraine ceased. The moraine tken extruded, 
being all left subaqueously, retained its original unwasked form of 
Glacial (Erie) clay, similar in ckaracter to tke Upper Glacial clay of 
England, wkick was left beneatk tke sea by tke retreat of tke ice- 
sheet during tke general submergence of Britain. If tkis view be 
sound, tke age of tke Okio Karnes and Eskers wkick, following tke 
sequence assigned to tkem ky Prof. Newberry, I have called Sb, 
would really be that of tke oldest portion of the Okio Glacial series, 
viz. coeval witk tke Erie clay (No. 1), of wkick tkey would con- 
stitute in tke horizontal sequence of Glacial deposits tke earliest 
portion. 1 
The occupation of the Canadian kigklands by an ice-skeet sub- 
sequently to tke growtk of tke forest over tke Erie clay seems to me 
to conspire witk the evidence afforded by tke recent ckaracter of 
tke mollusca of tke Leda, Ckamplain, and other marine clays of tke 
lower kasin of tke St. Lawrence, and Atlantic coast, to skow tkat 
1 Prof. Newberry observes that only patches of tbe Erie clay occur on the water- 
parting whicli is the region of these Kames, and in the details of sections that he 
gives, these Käme gravels do not rest on the Glacial deposits, but on the rock-surface. 
Mr. Geikie, in the second edition of his “ Great Ice Age,” similarly suggests that 
the Ohio Kames 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 fonned by the subaerial 
extrusion of the morame and that formed by its subaqueous extrusion. 
