24 
Earl R. Schejfel 
of drainage from a small valley {S. F., fig. i) connected with the 
spur. The eskers and kame area spreading southward from the 
Blulfs cut off a small segment of the Great Miami Valley {F. S., 
fig. i) lying south of the spur. 
Theories of origin. In diagrammatic view (fig. i) the valley 
of Dayton appears as an oblong basin with wide gaps for the en- 
trance of the Miami River and tributaries, and one for the depar- 
ture of the combined drainage. This great basin may have ex- 
erted an important influence on the waning glacial ice in control- 
ling its movement in this area, and also in concentrating drainage 
that became sub-glacial.^® That this basin and its tributaries do 
represent glacial drainage lines^^ is proved by the great depth and 
character of the debris filling. The over-riding ice would drop 
into the Dayton valley as in a pocket. This in the stagnant ice 
stages would accentuate its immobility thereby conducing to esker- 
forming conditions. The concentrated drainage would seek the 
point of easiest egress which would probably be somewhere in 
the gap to the south. While under great head, as doubtless the 
drainage would be at times of most active ice-melting, topography 
might to some extent be disregarded. This could explain the 
appearance of the ridges on the eastern side of the valley gap (pos- 
sibly even superimposed over a continuation of the rock spur) 
rather than in the center.^® 
The close association of the eskers with kame deposits suggests 
that the latter were formed during the retreat of the ice after the 
eskers had been built in sub-glacial stream tunnels. This kame 
area doubtless spread originally further across the valley but has 
in part been removed by the meanderings of the Miami River. 
The abrupt face presented to the north by the Bluff's may also have 
the same explanation; it has already been noted that this river 
flows at the present time along their base. If this explanation is 
correct, the kame and esker topography may formerly have ex- 
tended an indefinite distance northward into the Dayton valley. 
1 . C. Russell, Jour, of GeoL^ vol. iii (1895), p. 827. O. H. Hershey, loc. cit.^ 
p. 240. 
F. Leverett, loc. cit., PI. II. 
Chamberlin and Salisbury, loc. cit., p. 375. 
