242 PLEISTOCENE OP INDIANA AND MICHIGAN. 



from Ithaca along the line between T. 10 N., Rs. 2 and 3 W. (Newark and North Star townships) 

 and then turns southwest through central T. 9 N., R. 3 W. (Fulton Township) to the Grand 

 River channel north of Maple Rapids. (See fig. 1, p. 258.) The first ridge, which appears to 

 have run southward from near Perrinton across the channel 1 or 2 miles northeast of Maple 

 Rapids, is clearly out of harmony with the second, which appears to project as a sharp tongue 

 down the channel. It looks as if the first moraine was built before the channel was in existence, 

 and that the second one came later, after the channel had been made, and that the ice was 

 guided by the channel in the formation of the sharp tongue. The topography on the 'south 

 side of the channel seems to support this view, for the moraines there are broken and irregular, 

 thouo-h two main ridges corresponding to the two on the north side are easily made out. The 

 first, which may be called the Flint moraine, seems certainly to be a continuation of the Per- 

 rinton Ridge, which would run into it if produced southward. It begins abruptly on the south 

 side of Maple River as a high, steep bluff rising close above the stream. For 2 or 3 miles to the 

 southeast it runs as a double ridge with a small, narrow clay flat between, the eastern ridge being 

 the smaller of the two. From this on for 9 or 10 miles east to Duplain it is represented only 

 by scattered knolls in a flat clay plain which is sometimes swampy. 



Beyond Duplain it reappears as a strong ridge and 2 miles east of the village makes a sharp 

 loop to the north around a flat hollow about 2 miles in diameter. This hollow is almost sur- 

 rounded by the moraine, remaining open only to the southwest. On account of this irregularity 

 the moraine has unusual breadth north of Ovid. East of Ovid it is cut through by an esker 

 trough which enters from the northeast, turns west, and runs nearly parallel with the moraine. 

 At its mouth it contains an esker nearly a mile long, which also parallels the moraine, a very 

 exceptional course for an esker. 



Some of the irregularities in this moraine from Maple Rapids to Ovid may be due to a 

 readvance of the ice, but others appear to be due directly or indirectiy to the presence and 

 influence of the great outlet river which flowed close along the front of the ice at that time. 

 The moraine grows unusually wide again south and west of Owosso and is cut through by 

 a wide, low trough. Shiawassee River cuts through it at Vernon and a smaller stream northwest 

 of Duffield. With these exceptions it runs with even strength from Ovid to Flint. It is promi- 

 nent and controls much of the drainage. From Ovid to a point north of Durand it runs a little 

 south of east, but between Vernon and Duffield it curves gradually around through east to 

 east-northeast and keeps this direction to Flint. From Corunna east it is half a mile to a mile 

 wide and rises 30 to 50 feet above the channel floor south of it. Its trend on entering the 

 western part of Flint is east-northeast. 



Flint seems to be situated at the former apex of a blunt ice lobe, for a probable continuation 

 of the moraine runs north from the north side of the river nearly to Mount Morris and there 

 turns northeast and passes near Thetford into Tuscola County. Flint River here follows the 

 last position of the Imlay outlet channel. It enters Flint from the northeast and turns west- 

 northwest, cutting a gap about a mile wide through the moraine. The moraine on the north 

 bank is weaker for 2 or 3 miles than the one west of Flint and seems to stand somewhat out of 

 line with it, even if the apex of a lobe was at Flint. Still, it is almost certainly the continuation 

 of the Flint moraine. The lack of alignment suggests that the part north of the river may 

 represent only the inner part of the Flint moraine. 



Other facts give some support to this supposition. A well-defined bowlder belt which 

 runs northeast from Flint to the river south of Rogersville rests on the flat till plain, but may 

 represent the continuation of the outer part of the Flint moraine, for the morainic features farther 

 northeast seem to require the continuation of the ice front across this bowldery interval. 



Another strong morainic area lies just south of the river on the township line east of Genesee 

 and still another smaller one on the north side a mile northeast of Genesee; perhaps both 

 belong to the Flint moraine, but their relations are not entirely clear. In the northwestern 

 part of Richfield north of the river, however, morainic knolls appear and increase rapidly in 

 strength and continuity toward Otisville,. forming what may be termed the Otisville moraine. 

 They grow still stronger farther northeast on the north side of the railroad to and beyond the 



