Jan., 1908.] 
An Esker Group South of Dayton. 
' 2 39 
eastward. The fanning of the knoll-endings into the valley 
where they meet in an even slope is doubtless the result of slump¬ 
ing. Davis 21 gives a clear exposition of conditions when bodies 
of water are dammed by the ice-front, with the consequent 
phenomena of sand plains built up by esker streams. The Day- 
ton area, however, shows no evidence of favorable conditions 
for the holding of ice-front waters, drainage having a perfectly 
free course toward the south. Streams emerging from the ice 
would spread out and quickly drain away. In this particular 
area such an outwash plain if formed would have been destroyed 
long ago by the erratic wanderings of the Miami. 
Fig. 5 (F. Carney ). Kame area immediately west of esker No. 2. Camera 
facing north. Barn rests on a long ridge of kames. 
Altitude of These Deposits. The elevation of the area above the 
valley is partly due to the base upon which it rests. This is 
shown particularly in the kame region, the inside slopes of which 
are much shorter than the slopes facing the valley, a condition 
explainable by slumping within the area and erosion around it 
by the Miami as before stated. 
In this connection it may be suggested that possibly gradation 
has greatly modified the original eskers. At the time of ice- 
withdrawal these forms, particularly if sub-glacial in genesis, 
must have been left with little or no vegetative protection. It 
cannot be determined how long a time was required before plant 
life secured a good foot-hold, but it is reasonable to suppose that 
the interval was sufficient to permit considerable weathering even 
on such narrow forms as eskers. With the eskers in question is 
it not probable that after the constituting material had assumed 
its natural angle of repose they may have been considerably 
lowered by gradational processes? Such processes would also 
reduce the effect of height by partially filling the trough. ■ • 
21. W. M. Davis, Bull. Geol. Soc. Am, Vol. I, (1890), pp. 195-203. 
