S. V. Wood,jun. — American and British Surface- Geolog y. 493 
this water-parting, and so invaded the lake-basin, sotne marine 
organisms do not occur in the deposits of that basin. Not only does 
Prof. Newherry make no mention of any such, but Mr. Hinde, in a 
paper in the Canadian Journal for April, 1877, insists that uone but 
land and fresh water organisms have occurred in them. It seems to 
me, therefore, in the absence of better explanation, that the gravels 
thus occupying the Ohio water-parting are not of marine origin, but 
have come into existence in a different way altogether, viz. : 
Not having seen the Karnes and Eskers of Ohio, or even those of 
Ireland, I of course can only form my opinion by analogy ; but 
those of Scotland I have seen throughout most of the Highlands of 
that part of Britain, and on both sides of them as far north as 
Inverness: and it appears to me that Mr. Jamieson’s view of their 
origin, from the melting subaerially of ice which formed in the 
mountain districts of Scotland posterior to the emergence of our 
island from its great depression, is the correct one. Not only so, 
but nothing to my mind is more confirmatory of the view for which 
Prof. Newberry and I contend of Glacial clay, or Till, having had 
a submarine origin, than the contrast afforded by this Esker and 
Karne drift. When a glacier terminates in the sea, or a lake, 
the moraine material extruded and left behind by it in its recession 
is only washed out into gravel where it is subjected to current 
action. This action is exceptional, and may perhaps be induced 
by the outflow here and there of streams of freshwater from beneath 
the ice. In whatever way, however, the currents be caused, the 
formation of gravel during morainic extrusion with submergence 
seems to me to be partial, and the great bulk of the material to be 
accumulated in the unwashed form, because nearly all the glacier- 
ice is either carried away piecemeal from the termination of the 
glacier in the form of bergs, to dissolve elsewhere, which is the 
case where the water is deep enough ; or eise it wastes imperceptibly 
away into the sea that washes the glacier, which is the case where 
the glacier terminates in water too shallow to give rise to bergs. 
When, however, the glacier ends short of the sea, i.e. on land, these 
conditions are reversed ; for all this ice dissolves in the glacier itself, 
and pouring from beneath it as water forms a torrential river, wash- 
ing out the moraine material into gravel, which the glacier as it 
recedes leaves in heaps and ridges, while the muddy particles are 
carried off in Suspension by the river. Thus, it appears to me that 
the unfossiliferous gravel which forms the principal part of the Drift 
of the Scottish Highland valleys arose from the melting back sub- 
aerially of the nonconfluent glaciers of the Hessle period. This 
period I contend was one of limited re-submergence which, reaching 
its maximum during the deposit of the Hessle clay, was confined 
to the northem parts of Britain. It is also the period, as it seems 
to me, during which the Glenroy roads were formed; and I observed 
that near the sea or the great lochs in the Southern extremity of the 
Highlands, the moraine material consisted principally of gritty 
Boulder-earth, and at the northem extremity, as about Inverness, 
it passed downwards into similar earth ; while in the higher valleys 
