MORAINIC SYSTEMS AT HEADS OF LAKE MICHIGAN AND SAGINAW BASINS. 177 



One isolated knoll 3 miles east of Laporte in sec. 33, T. 37 N., R. 2 W., rises about 50 feet 

 above the bordering gravel plain and readies an altitude of 850 feet above sea level. It is sep- 

 arated from Rolling Prairie by the valley of Little Kankakee River. 



STRUCTURE OF THE DRIFT. 



COMPOSITION. 



Throughout the length of both ridges of the Kalamazoo system the drift is mainly assorted 

 material of various grades of coarseness. There is at surface either a loose-textured stony 

 clay or a sandy drift, everywhere carrying a liberal supply of bowlders. On some of the sandiest 

 knolls bowlder piles may be seen in the cultivated fields, and on many of the clayey ones bowlders 

 are so numerous as seriously to hinder cultivation. The general thickness of the capping of 

 bowldery clay is only a few feet. Loose sand and gravel is reported to underlie wide areas at 

 a depth of less than 10 feet. In places a brown or blue clayey till underlies the looser-textured 

 or more stony surface clay: and in places clayey till is struck at moderate depths beneath sand 

 and gravel in both the morainic system and the outwash tract east of it. But the general preva- 

 lence of thick beds of sand and gravel is shown by numerous well records, supplemented by 

 natural exposures near streams and on the edge of the basins of the small lakes. 



THICKNESS. 



Some wells have reached depths of over 200 feet without penetrating much till or striking 

 bedrock. Some of the deepest wells are found on the border of the Kalamazoo Valley and 

 northward from there into the interlobate spur north of Prairieville. From Kalamazoo south- 

 westward most wells are only 75 to 80 feet deep, though a few are 150 to 160 feet. 



In sec. 15, Rutland Township, Barry County, J. Belson bored to a depth of 210 feet from 

 an altitude of about 870 feet without striking rock. Water was found at about 100 feet and 

 the well completed to that depth, the lower part of the boring being through fine sand that did 

 not increase the yield of water. 



In sec. 11, Orangeville Township, Barry County, a well made by Mr. Stewart on ground 

 about 975 feet above sea level reached a depth of 150 feet and was entirely through sand and 

 gravel after passing through 10 feet of brown stony clay at the surface. Water was found 

 only in the lower 20 feet. In the vicinity the brown stony surface clay was found to range in 

 thickness from 3 feet up to 16 feet or more, the greatest thickness being in basins. Several 

 wells have reached depths of 150 feet or more without encountering any till except that at 

 the surface. 



In sec. 28, Orangeville Township, two wells, starting at an altitude of about 950 feet and 

 having depths of 208 and 196 feet, are reported to have been in sand and gravel after passing 

 through the thin surface bed of brown stony clay. 



Near Prairieville some wells 75 to 100 feet in depth have penetrated thin beds of blue clay 

 at about 30 feet from the surface as well as 6 to 8 feet of the brown surface clay. A well in 

 sec. 15, Prairieville Township, penetrated reddish-brown till 10 feet, sand 20 feet, gravel 30 feet. 



A well in sec. 1, Cooper Township, Kalamazoo County, on the farm of Mr. Haskins, is 120 

 feet in depth and shows scarcely 20 feet of clay. A well near by penetrated 40 feet of brown 

 stony till and 43 feet of dry sand, obtaining water in gravel at the bottom. A well in the 

 south part of the same section on the crest of the outer ridge of the Kalamazoo system at an 

 altitude of about 975 feet penetrated alternations of gravel and very stony till throughout its 

 entire depth of 130 feet. Another well 100 rods west, on somewhat lower ground, penetrated 

 reddish-brown till 30 feet, sand 40 feet, reddish brown till 25 to 30 feet, and water-bearing 

 gravel 8 to 10 feet. 



On the west side of Kalamazoo River, in southern Cooper Township, several wells on the 

 outer ridge of the Kalamazoo system are 100 to 160 feet in depth and are largely through sand 

 34407°— 15 12 



