ICE WORK IN SOUTHEASTERN MICHIGAN 215 
Laurentide ice seems justified. About the western end of Lake 
Erie where the strike of the softer beds coincided with the 
direction of ice movement, broad, shallow troughs were exca- 
vated. 
4. A second general movement followed west-southwesterly, 
intermediate in point of time between the Illinoian and early 
Wisconsin and less vigorous than either. This glaciation prob- 
ably represents the Iowan. 
5. The third ice movement was south-southwestward, second 
in vigor and massiveness only to the Illinoian and presumably 
capable of attaining also a low latitude. This is quite certainly 
the early Wisconsin. This ice is believed to have produced the 
series of outer discordant moraines in southern Ohio and Indiana. 
With this evidence, so far back from the southern limit of the 
Wisconsin ice, of distinct difference in direction of movement, 
in steadiness, vigor, and massiveness, more of a break between 
the early Wisconsin and late Wisconsin probably existed than 
has been yet recognized. 
6. The fourth and final movement was the late Wisconsin, 
which resulted in the formation of the concentric morainic loops 
of northern Indiana, northwestern Ohio, and eastern Michigan. 
The ice was more influenced at this stage by the topography 
than at any previous time, was less vigorous and presumably 
less massive. The movement was in the main southwestward, 
but upon the upper side of the Huron-Erie lobe was outward 
toward the moraines, having less and less effect upon the rock 
surface. As the ice front retreated northeastward water was 
ponded back in the low country of the Maumee valley, Lake 
Erie region and southern Lake Huron and the series of glacial 
lakes was formed. 
7. In the region under report the rock surface was lowered 
but slightly by the three later ice-sheets, the amount to be 
expressed most probably in inches. Knobs and trails produced 
by the early Wisconsin in exposed position are but slightly 
affected by the late Wisconsin. Moderately heavy gouges and 
strie of the early Wisconsin escaped obliteration in many 
