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 anv 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 sti-ong 

 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 

 liypotliesis 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 



