152 BULLETIN OF THE 
The gradual increase in the measure of this irregularity of the super- 
ficial sands, as we proceed from the shore towards the higher country, 
clearly indicates that it is due to some cause the energy of which was 
measured by the elevation of the surface above the sea. Moreover, the 
fact that these ridges lie upon subjacent rocks of somewhat varied age 
and composition, appears to indicate that they are not dependent on 
any subterranean influences, such as the erosion or corrosion of the un- 
derlying rocks. : 
When I first came in sight of the lake district of Florida, the imme- 
diate impression was that I had entered upon a kame district, a region 
of pitted plain analogous to the kame belts along the New England 
shore near the ancient frontal moraines, but on a far larger scale. 
The surface has almost exactly the topography of the central part of 
Nantucket, or the field of kame plain to the eastward of the Eliza- 
beth Island moraine, where that lies at the base of Cape Cod between 
Wood’s Hole and Sandwich. It seems to me certain that any geologist 
familiar with this topography would, if taken blindfolded and ignorant 
of his route to the lake district of Florida, at once come to the conclu- 
sion that he was in a kame district of New England. Whatever were 
the other circumstances under which our kames were formed, there can 
be little doubt that they are the product of water flowing. I have else- 
where argued that ordinary kames are in the main, if not altogether, 
due to the tossing about of glacial waste under the influence of strong 
currents pouring from beneath the glacier into a water area where 
mobile sediments were being laid down. 
Although at first I endeavored to account for the peculiarities of the 
surface in this lake district on the hypothesis that the warped surface 
was produced by subterranean erosion, I was in the end forced to the 
hypothesis that these ridges represented the action of strong currents, 
which served to move the sands, either in air or water. I then ad- 
dressed myself to the task of determining which of these two agents of 
transportation had given shape to the surface. I found myself quickly 
driven from the hypothesis that these hills were due to the action of 
the wind. In the first place, the gradual increase in the measure of 
relief, as we go from the sea to the higher lands, is obviously against 
the hypothesis of wind action. Next we note the fact, that on the ex- 
isting coasts of Florida the dune building is slight in amount, though 
the sands have in many places substantially the same character as those 
which compose these hills. Furthermore, the shape of the hills is not 
that presented by any of the extensive dune districts which I have 
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