214 W. H. SHERZER 
cate less vigorous ice action than the strie upon the opposite, 
or westward side of this mean. 
Western portton—Upon the western rock ridge the finest 
exposures of striz are to be found north of Dundee about the 
mouth of the Macon River.) “As these: aresini the bedmot the 
Macon and Raisin, the best time for a visit is in the late sum- 
‘mer or early fall when the water is low. The past season proved 
favorable and a satisfactory set of readings was obtained. The 
most conspicuous scorings to be found were made by the early 
Wisconsin, thirty-six observations giving a mean of S, 32.2° W., 
with) a) range of 46:5 (S375 W. to S50 rW)na he anol: 
ledges in the bed of the Raisin, just below the entrance of the 
Macon are heavily gouged by this series. The late Wisconsin 
sheet seems to have had but little effect upon the rock surface 
as the series of moraines was approached. At but one locality 
in the bed of the Macon are any striz of this series to be found, 
giving a mean of N. 74.3° W. The movement becomes more 
westerly as we pass southward and south of west as the Ohio 
boundary is reached. At the head of Ottawa Lake a limited 
exposure shows the two sets S. 89° W. and S. 21° W. Just 
north at the quarries the few readings averaged S. 70° W. and 
Se2se We At ‘the: “Inlet ma single: gouge:uns:S: 65° W. and 
three miles to the southeast in the bed of Halfway Creek four 
readings were obtained giving a mean of S. 56° W. In thus 
passing southward we approach the main axis of the late Wis- 
consin lobe and its striz again predominate over those of the 
early Wisconsin. 
GENERAL CONSIDERATIONS. 
1. There is no evidence in this section of Michigan of any 
general southeasterly ice movement. 
2. All the scoring action observed may be referred to four 
stages in the history of the Laurentide ice-sheet. 
3. The first and oldest ice movement was to the southwest, 
being the most vigorous of all, quite independent of topography 
and presumably the most massive. Parallel with the main axis 
of the Illinoian glaciation its reference to this stage of the 
