238 PLEISTOCENE OF INDIANA AND MICHIGAN. 



across Isabella County it is spread out in a plain 2 to 5 miles wide, composed largely of fine sandy 

 gravel, as in the glacial drainage line to the west. 



The glacial drainage connected with the Gladwin moraine probably passed southwestward 

 through narrow channels between morainic ridges in western Gladwin and southeastern Clare 

 counties, though the details have not been worked out. From the village of Clare a well-defined 

 border drainage channel, filled with a sandy outwash, leads southwestward to the Chippewa 

 Valley, southward from which a depression on the outer border of the moraine leads into Gratiot 

 County. So far as noted this depression is nearly free from sand or gravel deposits, but it seems 

 likely, nevertheless, to have been followed by the glacial waters. In Gratiot County a low 

 plain lies west of this weak morainic belt but appeal's to bear little outwash. The writer has 

 not made a detailed study along the moramic belt, but there appears to have been no obstruc- 

 tion to the southward passage of water along the outer edge of the ice into the Grand River 

 outlet through western Gratiot County. 



MORAINES OF THE EASTERN LIMB OF THE SAGINAW LOBE. 



By Frank B. Taylor. 



DISTRIBUTION. 



GENERAL FEATURES. 



The moraines of the southern and eastern borders of the Saginaw lobe lie between the 

 Grand River channel and the west line of Lapeer County. Grand River channel, which will be 

 fully described later (pp. 255-259, 360), extends westward from Gratiot County to Lake Michigan. 

 It is occupied from southeastern Gratiot Comity by Maple River, which flows westward and south- 

 westward as a sluggish stream wandering on a swampy floor of a mile-wide valley. It is entered 

 from the south by Grand River at Lyons, about 40 miles east of Grand Rapids, and it 

 takes its name from that stream throughout its length of about 75 miles. It cuts directly 

 across the West Branch-Gladwin group of moraines, on a line a little north of the central axis 

 of the Saginaw Valley produced southwestward. 



That part of the West Branch-Gladwin group of moraines which lies north of the Grand 

 River channel (described by Mr. Leverett, pp. 232-238) generally shows much complexity in the 

 northern part of the State, although clearly separate from other moraines which preceded and 

 followed it. 



North of West Branch the deposits have the appearance of a single massive moraine of 

 irregular form, but in their extension southward to the vicinity of Harrison and Gladwin they 

 change remarkably to a complex of short morainic ridges, overlaps, spurs, loops, and irregular 

 knolly patches. Farther south they divide and spread more and more widely into separate 

 individuals with roughly parallel courses. At the north side of the Grand River channel the 

 deposits have a width of nearly 40 miles, and 5 to 10 miles farther south their slender ridges are 

 more perfectly set apart as individuals, spreading over a width of more than 50 miles. This change 

 in form from an essentially single, massive individual to many slender, distinct individuals is 

 not equaled in any other locality now known. 



The distribution of the moraines in the district is dependent in part at least on the relation 

 of the Saginaw ice lobe to the topography. As the ice advanced out of the deeper basin of Lake 

 Huron, it deployed on all sides upon a relatively smooth plain that sloped very gently upward in 

 all directions. The upward slope was a little less toward the south than toward the west and 

 was still less toward the southwest. The ice adapted itself to the form of the wide, shallow 

 basin with minute fidelity. Its front took on an unusually symmetrical form, now revealed by 

 the configuration of the terminal moraines. A straight line drawn from the center of Saginaw 

 Bay (about 20 miles northeast of Bay City) southwestward to the village of Hastings in Barry 

 Comity divides the moraines into almost perf ectly symmetrical halves. The symmetry is perhaps 

 a little more perfect if the division is along a line 5 to 10 miles southeast of and parallel with the 

 real axis. The best developed area is in Clinton, Ionia, Shiawassee, northern Eaton, and 



