362 THE ILLINOIS GLACIAL LOBE. 



On the overwash gravel plain in western Martin Township, Allegan 

 County (T. 2 N., R. 11 W.), a well in the northern part of sec. 20 pene- 

 trates sand and gravel 50 feet; beneath this a hard blue bowlder clay 100 

 feet. The well was abandoned without reaching the bottom of the clay. 

 A well in the southern part of sec. 6 penetrates the following beds: 



Section in icell in Martin Township, Allegcm County, Michigan. 



Feet. 



Loamy clay and gravel 5-6 



Cemented gravel 15 



Blue-gray till 12-15 



Gravel 6-8 



Quicksand 6-8 



Gravelly clay, slightly oxidized 30 



Blue-gray till , 30 



Gravel 1 



Depth 112 



Many wells on this overwash plain 40 feet in depth are entirely in sand 

 and gravel, after passing through the soil and a slightly cemented gravelly 

 and loamy clay 2 to 4 feet in depth. 



In an excavation made by the Grand Rapids and Indiana Railroad in 

 the southern part of sec. 17, Martin Township (T. 2 N., R. 11 W.), there is 

 an exposure 25 feet in depth revealing a mass of cobble, bowlderets, and 

 occasionally bowlders, in a bed of fine gravel. The pebbles are much 

 rounded, and in places are held together by a calcareous cement. A large 

 part of them are granites or other me.tamorph.ic or igneous rocks. One- 

 fourth to one-third are limestones, slate, and other local rocks. 



A well on Mr. Knickerbocker's farm, in sec. 2, Trowbridge Township 

 (T. 1 K, R. 13 W.), penetrates the following beds: 



Section in w ell in Trowbridge Township, Allegan County, Michigan. 



Feet. 



Soil and sand 20 



Soft blue clay with few pebbles 4 



Cemented gravel 7 



Loose gravel 15 



Blue clay apparently pebbleless 2 



Water-bearing sand 3 



Depth -■- 52 



A well 80 rods west from there, on Mr. Ipe's farm, 80 feet in depth, 

 passed through gravelly sand with very little clay admixture. Two miles 



