MORAINIC SYSTEMS AT HEADS OF LAKE MICHIGAN AND SAGINAW BASINS. 191 



THICKNESS. 



In the vicinity of the reentrant angle in Barry County, between the outer moraine of the 

 Kalamazoo system and its correlative in the Saginaw lobe, records were obtained of several wells 

 80 to 150 feet in depth, all of which terminate in drift. The bowldery surface clay is commonly 

 but 5 to 10 feet thick and is underlain to a considerable depth by sand. East of the reentrant angle 

 the lower parts of wells contain till, alternating with thin beds of sand and gravel. There are, 

 however, considerable areas in which very little till occurs except in the thin sheet at the surface. 

 Many wells reach depths of SO to 90 feet. Some penetrate a blue quicksand, generally beneath 

 blue till, but in most of them the sand is gray or yellowish and is moderately coarse. 



In Calhoun County west of Battle Creek records of wells 100 to 125 feet deep show a large 

 amount of assorted material, some of which is described as reddish sand and some as gravel and 

 sand. In sec. 16, Penfield Township, two wells, 110 and 125 feet deep, stand on a very 

 prominent portion of the moraine 80 to 100 feet above the valley of Battle Creek. The 110-foot 

 well has the following record: 



Record of well in Penfield Township, Calhoun County, Mich. 



Feet. 



Bowlder clay, yellow 15 



Bowlder clay, blue-gray 4 



Cobble, gravel, and sand 50 



Sand, reddish _ 35 



Gravel and water 6 



110 



In much of Convis Township, which lies east of Battle Creek valley, the drift is verj^ sandy, 

 but in the southwestern portion the soil is heavier and the wells encounter considerable bowl- 

 der clay, though even here some wells are largely in gravel and sand. In the vicinity of the 

 swamp in Lee Township wells are reported to penetrate a slightly pebbly blue-gray clay. 

 In northern Marengo Township wells penetrate yellowish till for 8 to 15 feet and then com- 

 monly enter dry sand, though some find bluish till. In the northeastern townships of Calhoun 

 County the wells indicate that the drift is mainly sand and gravel; some of the wells pass into 

 rock at depths of 50 feet or less. 



The spur which runs northward into Eaton County along the east side of Battle Creek con- 

 tains considerable clayey till, but carries gravel knolls and a short esker. Some of the wells are in 

 sand or gravel in their lower and clayey till in their upper part. Native copper is reported from 

 the drift about Olivet. Knolls in the village of Olivet are gravelly, but some of them are shown 

 by wells to contain a blue till at about the level of their base. 



In northwestern Jackson County sandstone is entered in most wells at depths of less than 50 

 feet though in some the drift goes down about 100 feet. It is commonly sandy or loose tex- 

 tured throughout but is not definitely assorted, the sand being derived from the local sandstone. 



The strong moraine leading eastward from Jackson is gravelly and so far as ascertained con- 

 tains but little clayey material. Many of its knolls show abrupt changes from sand to gravel 

 and cobble. North of the Portage marsh sand in places forms but a thin cover over the till ; wells 

 are obtained at slight depth (some after penetrating only 5 or 6 feet of till) , and the extent and 

 depth of the till is not known. 



INNER BORDER. 

 GENERAL CHARACTER. 



Only narrow strips of plain lie between the Kalamazoo and Charlotte, morainic systems and 

 between the constituent ridges of the Kalamazoo system. The strip between Marshall and Char- 

 lotte is the widest, attaining a width of 15 miles; the ordinary width is less than 10 miles. The 

 strip between the outer and second ridges in Jackson County is nearly 6 miles wide where widest. 

 Along Portage River it is largely a sandy swamp, but west of Grand River it is a cultivable 

 till plain, traversed by a sharp esker ridge. A small area of cultivable sandy till lies north of 



