42 . GEOLOGY OF OHIO. 
resemble them are in the lines of the old waste-weirs, through which 
the surplus water flowed from the lake-basin to the Ohio. In the Miami 
Valley are hills of well-rounded gravel, not unlike the Kames in general 
character, but they are mostly composed of limestone pebbles derived 
from the upper portion of the valley, and are remnants of sheets of val- 
ley-drift, eroded by the present streams. 
That the kames of the water-shed have been formed by the action of 
water on the morainic material of the Erie clay, seems certain, but how 
the necessary floods of water could be preduced there, is a difficult problem. 
Up to the present time no more plausible explanatory hypotheses than 
those mentioned have suggested themselves. 
8 
ICEBERG DRIFT. 
Most recent writers on the surface geology of North America, have 
given to icebergs a more or less prominent part in the distribution of the 
Drift material. By some they are nfade the chief agent, both in the 
scoring of the rocks and in the transportation of clay, sand, gravel, and 
bowlders, but we have shown that both the erosion and transportation 
were chiefly affected by glaciers. Another party has denied altogether 
the agency of icebergs in producing the phenomena of the Drift. Promi- 
nent among the latter is Prof. N. H. Winchell, who has written volumi- 
nously on the Drift deposits, particularly those of the north-west. He 
attributes all the phenomena of the Drift to glaciers, denies the littoral 
origin of the so-called beaches of the lake basin, considering them mo- — 
raines, and intimates that the four hundred feet beach, near Montreal, 
may come into the same category.* Hvery unprejudiced person must, 
however, admit, from the facts given in our second volume, that icebergs 
did at one time float over the waters that filled the lake basin, transport- 
ing and depositing more or less of the material now found on the surface 
of Ohio. Several instances of the occurrence of large striated bowlders, _ 
buried in laminated clays, where they must have been floated and dropped 
from an ice-raft, are referred to in Chapter XXX. Another instance which 
has recently come under the observation of the writer, is equally conclu- 
sive of the presence of icebergs in the lake basin. In cutting down the 
cliff of clay on the lake shore, near the Union Depot, at Cleveland, in 
1876, a large striated bowlder of gneiss was found bedded in the finely 
laminated clay, (the upper and stratified portion of the Hrie clay), some 
twenty feet below its surface and forty feet above the lake. That this 
stone had come from the Canadian highlands, had once been imbedded 
in an ice-raft, and was dropped into the clay that was being deposited at 
the bottom of the lake, when its surface was very much higher than now 
* Drift Deposits of the North-west, Popular Science Monthly, July, 1873, p. 219. 
