98 PLEISTOCENE OP INDIANA AND MICHIGAN. 



to White River. In many places they lie in north-south chains or nearly at right angles to the 

 trend of the moraine. 



A little farther west, in southern Delaware and northern Henry counties, a complex system 

 of winding ridges incloses basins and marshy tracts, in which the East White River gravel 

 plain begins. The marshy tracts drain southward into a single large channel in the northern part 

 of Henry County. 



From the head of this channel to Mount Summit a system of ridges and knolls rises abruptly 

 75 to 100 feet above bordering swampy tracts. Its sharpest ridges lie back about 2 miles from 

 the edge of the gravel plain, the intervening space being gently undulating and thickly strewn 

 with bowlders. 



Randolph and Wayne counties. — In southern Randolph and northern Wayne counties, Ind., 

 the moraine covers an uneven surface of uplands and lowlands, the. lowlands being occupied 

 by the headwater branches of Whitewater River. The ice sheet apparently overhung valleys 

 which had been cut in the drift and deposited its knolls on the slopes and bottoms. Oscillation 

 may have resulted in an overriding of the heads of the lines of glacial drainage. The knolls of 

 this region are closely aggregated and thickly strewn with bowlders, but very few of them reach 

 a height exceeding 30 feet. 



STRUCTURE OF THE DRIFT. 



COMPOSITION. 



In most of the region traversed by the Bloomington morainic system the superficial portion 

 of the drift is a yellow till bearing a few scattered gravel knolls, but in a district comprising 

 several square miles in southeastern Delaware and northeastern Henry counties, about the head 

 of the East White gravel plain (Collett's glacial river), knolls, ridges, and intervening marshy 

 tracts alike are composed largely of gravel. Gravelly knolls and narrow strips of flat-surfaced 

 gravel also occur along certain valleys where the bordering uplands are till. Throughout this 

 region the percentage of gravel is generally larger in the steep knolls than it is in the low swells, 

 the latter as a rule being composed of till. It is not rare to find hills from which all the gravel 

 has been removed for commercial use, leaving only till. In some hills the gravel is confined 

 to one side; in others it forms the body of the hill, the superficial portion being till; and in still 

 others it is in pockets on the surface, the body of the hill being till. Throughout the morainic 

 belt in Indiana the gravel is conveniently distributed for use on the roads. 



CONTACT OF WISCONSIN AND PKE-WISCONSIN DRIFT. 



The occurrence of buried soil found in wells of southwestern Boone County (records of which 

 follow) is of service in dividing the drift into earlier and later sheets, the portion above the 

 buried soil being probably of Wisconsin age. 1 



Section of Shelly well, 4 miles north of Jamestown. 



Feet. 



Soil and yellow clay, mixed with sand 12 



Sand, yellow 2 



Gravel, hard 4 



Hardpan gravel 4 



Sand, white 6 



Sand and clay, bluish 18 



Muck or loam, black, with branches of trees and other vegetable matter 12 



Clay, blue 4 



Sand, gravel, etc., gray 26 



i These records are from the Fifteenth Ann. Rept. Indiana Dept. Geology and Nat. Hist., 1886, pp. 166-173. 



