368 PLEISTOCENE OF INDIANA AND MICHIGAN. 



into the edge of a wood lot, where it is cut away, apparently by a former meander of the river 

 winch swung to the east and cut heavily into the high ground. 



The situation of the third beach in sec. 8, Grant Township, is truly remarkable. On 

 the road east from Spring Hill the third beach is a trifle more than half a mile west of the river, 

 and it runs at a short distance from the bluff all the way up to sec. 8. In this same interval 

 the rather steep and bold front of the main moraine of the Port Huron system lies close along 

 the east side of the river and in some places is cut by the meandering of the stream. Through 

 sees. 29, 20, 17, and the south half of sec. 8 the foot of the moraine is close to the river. At 

 the little fragment of beach on the east side in sec. 8 the foot of the moraine comes actually 

 .in contact with the eastern edge of the beach ridge and a distinct but narrow trough or depres- 

 sion intervenes between the beach and the foot of the moraine. This depression is scarcely 

 more than 50 feet wide; indeed, its slopes consist of the two formations mentioned. Its west 

 side is the eastward face of the gravel ridge, and its east side is the westward face of the moraine. 

 This attitude of face to face contact between the strongly formed beach and the great moraine 

 has not been observed elsewhere, so far as known. From the little trough eastward up the 

 front slope of the great moraine — and this moraine is truly a great one — the surface of the 

 ground rises about 60 feet above the beach ridge within a distance of three-fourths of a mile. 

 The moraine is massive and rugged, and though its basal parts were laid down in shallow water, 

 its upper parts were land-laid and have the distinct hummocky, irregular surface characteristic 

 of such deposits. From its base at the beach ridge over its top and eastward down to the War- 

 ren beach along its eastern side is over 2 miles. The moraine fills this whole interval, and it 

 can scarcely be doubted that its thinning backward slope extends a mile or two farther toward 

 Lake Huron, or even to the lake shore. 



The fragment of the beach ridge in sec. 8 may have extended northward for some distance 

 and have been cut away by the meanderings of the river, but it is also possible that it was 

 buried under the moraine. In the north edge of sec. 8 and in sec. 5 the river has cut two dis- 

 tinct bights into the face of the moraine, and in these the beach ridge is missing. But in the 

 extreme northwest part of sec. 5 the gravelly beach ridge reappears once more on the east side 

 of the river and runs for one-fourth mile along the edge of the bluff. It is well formed here, 

 but is more nearly overridden by the moraine. Toward the north it is being cut away by the 

 river at its back and is partly buried by the moraine in front. It is again cut away on the bluff 

 in the southwest corner of sec. 32, in Worth Township 



One more small fragment of it reappears a quarter of a mile farther north, this time on 

 the west side of the river. Here its identity is perhaps more doubtful; but although it has 

 probably been modified to some extent by the river, it preserves quite distinctly the character 

 of a gravelly beach ridge with a slight depression behind it. This fragment is a quarter of a 

 mile long and is cut away at the edge of the bluff north and south. Farther north no evidence 

 of this beach ridge is found. Through Lexington and Worth townships an apron of fine sandy 

 outwash, one-half to three-fourths of a mile wide, slopes westward from the front of the moraine 

 to the river, and it seems quite probable that this outwash conceals the third Arkona beach. 

 It is a very surprising thing that the beach fragments which stand close against the front of 

 the moraine bear no outwash upon them, although the front of the ice was standing in 45 feet 

 of water. This is discussed in connection with Lake Whittlesey (p. 380). In the north half of 

 Worth Township and the south half of Lexington Township the front of the moraine turns 

 back a little to the east, and it may be that the third Arkona ridge is not buried under the 

 moraine until it reaches a point a mile or more north of Croswell, but is simply hidden under 

 the sandy outwash. From the south edge of Croswell an irregular sandy ridge runs south 

 about 2 \ miles. Except for about half a mile, this ridge lies on the east bank of the river and 

 from its position might be taken to be part of the third Arkona beach, but it is not a beach 

 formation. It is apparently composed wholly of fine sand and is very irregular, full of knobs 

 and irregular hollows, and is, in fact, a line of dunes. Thus the lower beach has been identified 

 for 7 miles north of the Spring Hill road. 



