LATER MORAINES OE LAKE MICHIGAN, SAGINAW, AND HURON-ERIE LOBES. 281 



OUTER BOEDER DRAINAGE. 



The flooded condition on the outer border of the moraine just noted is conspicuous only 

 south of the latitude of Ypsilanti. Northward from that city as far as Clinton River there is a 

 channel which appears to have had a southwestward-flowing current of water that was strong 

 enough in parts of its course to carry gravel of medium coarseness. In other parts pools existed, 

 and these are coated only with sand or fine material. It is probable that at the time of the 

 development of this moraine a small lake occupied a basin around Lapeer (see pp. 273, 274) ; its 

 correlation with this morainic system depends on the course of the Defiance moraine through 

 Lapeer County. 



BIRMINGHAM MORAINE. 

 By Frank B. Taylor. 



COURSE AND DISTRIBUTION. 



The Birmingham moraine appears to correspond to the Lyons moraine of the Saginaw 

 lobe. It is strongly developed from north-central Lapeer County down to the north bank of 

 Belle River, a mile north and west of Imlay, but from Belle River to Romeo it is weak. Just 

 north of Belle River and H miles west of Imlay morainic masses of considerable height, appar- 

 ently belonging to this moraine, appear to have pushed westward and closed the Lum channel. 



In the stretch of 2 or 3 miles west and southwest from Imlay there is nothing that seems 

 distinctly morainic. The surface is smooth with only the faintest suggestion of undulation or 

 ridging, but it is rather plentifully covered with bowlders. North and south through the cen- 

 tral part of this small plain area a belt nearly a mile wide, bearing almost no bowlders, is smoother 

 and flatter than the ground on either side of it. This strip is believed to mark the interval 

 between the Defiance and Birmingham moraines, the faintly undulating bowldery belt west of 

 it corresponding to the Defiance moraine and the narrow strip east of it to the Birmino-ham 

 moraine. 



The interval of 5 or 6 miles between Mill Creek northwest of Imlay and the south edo-e of 

 this bowldery plain is the only place where clear separation between the two moraines is lack- 

 ing. At the south edge of this plain a small tributary of Belle River flows eastward, crossing 

 the two moraines in sec. 36, Attica Township, and sees. 31 and 32, Imlay Township. 



In sees. 36 and 31 a small but well-defined glacial river bed, the Almont channel comes 

 from the northwest out of the flat area in the west-central part of Attica Township. This 

 drainage line is small but is remarkable for the persistence with which it keeps its way alono- the 

 west side of the belt of low bowldery knolls and gravel deposits which represent the Birming- 

 ham moraine from Imlay to Romeo. It is sinuous, especially between the southeast corner of 

 Attica Township and Almont, but it is not broken or interrupted. It is well developed at the 

 western edge of Almont and near the county line 4 miles south. 



It seems necessary to mention this channel in advance of the discussion of the glacial drain- 

 age of this district, because it is this drainage line more than anything else that makes certain 

 the continuity of the faint moraine between Imlay and Romeo. In the interval between the 

 southeast corner of Attica Township and Romeo — a distance of 12 or 13 miles along the chan- 

 nel — there are not less than 10 gaps in the low moraine to the east through which this stream 

 would certainly have flowed to the lower ground of the Imlay channel and Clinton River if they 

 had not been closed by the solid ice that was then resting on the moraine. It may be observed 

 also that a considerable part of the Birmingham moraine in this interval of weak development 

 lies below or east of the highest or first Maumee beach. From these considerations it is clear 

 that however weak and slender the Birmingham moraine appears to be in the interval between 

 Imlay and Romeo, it is nevertheless present and may be depended on in the correlation of mo- 

 raines, ice movements, and glacial drainage in this vicinity. In this interval of faint development 

 there is only one prominent knoll to mark its course, and this lies obliquely, extending 1 J miles 

 northeast from Almont. The reason for the faintness of the Birmingham moraine in this interval 

 will be discussed to better advantage in connection with the glacial drainage (pp. 283-284). 



