161 
probably still maintained. The High Gap Ridge is thought to be a moraine 
of the Michigan lobe. Later the ice retreated to the great moraine north of 
the Wabash, which river then extended itself from the great bend north- 
east along the border of the Michigan lobe in its present course. The lake 
held in the Wea basin then formed an outlet stream to the north and Wea 
Creek and its tributaries came into existence, the main stream following 
the moraine on the east and north sides where the deepest part if the lake 
vad been. The retreat continuing, the region east of Lafayette as far as 
Dayton, held a lake which flowed out where the moraine running east 
from West Point bends to the southeast at a low sag locally known as 
Dismal Swamp. Later an outlet opened into the Wea at the west end of 
the lake, the bed of which is now known as Wild Cat Prairie. Later still 
an outlet was formed at the east end of this lake by the South Fork of 
Wild Cat Creek extending headward from its junction with Middle Fork 
along the western border of the Hrie lobe. 
The Michigan and Erie lobes were now becoming differentiated again. 
The heavy moraine north of the Wabash is a terminal moraine of the 
Michigan lobe, the rapidly rising till plain east of the junction of Wild 
Cat Creek is the main frontal moraine of the Erie lobe. Tippecanoe River 
in its lower course is a former outlet of an interlobate lake which existed 
for a long time before being finally drained westward by the retreat of 
the Michigan lobe. The great gravel deposit is probably the filling of a 
lake produced by the melting of a thick bed of ice which had filled a pre- 
glacial valley. The present Wabash Valley is the trench cut out by the 
sand-laden stream which for thousands of years carried the water from 
the still retreating Erie lobe. 
Different layers of bowlder clay with beds of gravel interposed point 
to minor advances and retreats of the edge of the ice sheet over all the 
region. 
The facts here set forth are derived from an intimate knowledge of 
much of the region and considerable field work in the portions not so 
familiar and the conclusions are set forth as a working hypothesis subject 
to revision upon the basis of further examinations. The hypothesis postu- 
lates the presence of the Michigan and Erie lobes in the region at the same 
time, which is a view not agreed upon by all who have studied the glacial 
phenomena of North America. 
11—Science. 
