﻿8. V. Wood,jun. — American and British Surface-Geology. 493 



this water-parting, and so invaded the lake-basin, some marine 

 organisms do not occur in the deposits of that basin. Not only does 

 Prof. Newberry make no mention of any such, but Mr. Hinde, in a 

 paper in the Canadian Journal for April, 1877, insists that none but 

 land and freshwater 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 Kames 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 

 Kame 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 perha2:)s be induced 

 by the outflow here and there of streams of freshwater from beneath 

 the ice. In whatever way, however, tlie 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 glaciei"- 

 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 else 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- 

 aeriall}'' 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 northern 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 northern extremity, as about Inverness, 

 it passed downwards into similar earth ; while in the higher valleys 



