106 GEOLOGY OF OHIO. 
ing sufficient velocity to transport such a mass of coarse material several 
hundred miles, would not be shown simply in such transportation, but 
these currents would deeply excavate the underlying beds over which 
they flowed, and which were at this time scarcely in any degree consoli- 
dated. 1 
Shore waves acting upon this portion of the continent could not have 
effected such a distribution, as they have no power to create quartz peb- 
bles except as they have quartz rock to work upon. Advancing shore 
waves could, therefore, not have deposited two or three hundred feet of 
sand and gravel several hundred miles out upon a flat, composed alto- 
gether of fine material; and retreating shore waves would have no power 
to carry with them from Canada to Kentucky such a mass as the Con- 
glomerate forms there. We must, therefore, find some other process of 
distribution than any yet suggested for the explanation of the problem 
before us. 
In looking through the geological series for some similar deposit which 
could serve as an explanation of this one, I have found none that seemed 
to offer so close a parallel as the later Drift deposits spread over the 
northern half of the Mississippi valley. Here we have in many locali- 
ties a mass of material which, if consolidated, would form an almost 
perfect copy of the Carboniferous conglomerate—beds of gravel, in which 
the pebbles are for the most part quartz, undistinguishable from those 
of the Conglomerate and sheets of sand, nearly or quite free from peb- 
bles. It is true that most of the Drift also contains bowlders of larger 
size than any found in the Conglomerate, but over large areas these are 
restricted to the summit of the series, and mark a distinct epoch in the 
chain of events. Throughout a wide area, too, we find the gravels and 
sands of the Drift resting upon the lower, fine Drift clays, precisely as 
the Conglomerate rests upon the mud stones of the Waverly and the 
Sub-carboniferous limestone. To explain the phenomena presented by 
the Drift deposits, I have been compelled to invoke the aid of floating 
masses of ice, and have suggested that the gravels and sand which form 
the upper layers of the Drift have been floated to their present resting 
places, frequently from points of origin 500 miles distant, and quietly 
dropped down upon the soft clays below; arguing that currents of water 
or currents of ice transporting these gravels, sands, and bowlders, could 
not have deposited them where they are found without tearing up the 
underlying clays. | 
All that we know of the present sea bottom on the banks of New- 
foundland leads us to suppose that it is every where strewed with gravel, 
sand, and bowlders, spread with considerable uniformity over its surface 
