COKKELATIVES OF BLOOMINGTON MORAINIC SYSTEM. 107 



Probably the best-defined belts of western Indiana, though not associated with so strong 

 a moraine as that of eastern Indiana, represent transitory positions of the ice margin. As 

 already indicated the bowlder belts north of Wabash River in western Indiana cross the ridges 

 of the Bloomington system at various angles so as to show plainly that they can not represent 

 precisely the same ice margin that the ridges represent. 



INNER BORDER. 



In north-central Indiana a tract of about 4,000 square miles, extending from the Bloomington 

 morainic system northeastward to the Mississinawa morainic system and northward to Wabash 

 River, is without strong or well-defined moraines, though it has small tracts where the surface is 

 undulatory and a few places where bowlders are numerous. In general its surface is plane and 

 its drift is much thinner than on the belt south of it. This tract shows a westward descent of 

 200 to 250 feet in 45 miles, dropping from 1,100 feet at the Ohio-Indiana State fine to 850 to 900 

 feet on the meridian of Anderson. For 20 miles west from the Anderson meridian, in Madison, 

 Hamilton, and Tipton counties, the altitude is remarkably uniform. The southern part of the 

 tract then rises westward into the great drift belt in western Hamilton and southwestern Tipton 

 counties, ascending 60 to 100 feet in S or 10 miles. Farther north the tract very gradually 

 descends to the northwest toward the Wabash Valley, its altitude at the border of that valley 

 being about 700 feet. From the great drift belt in eastern Indiana northward about to White 

 River the descent is abrupt, being 120 feet in 10 miles from Bloomingsport to Winchester, 150 

 feet in 9 miles from ridges near Luray to Muncie, and 140 feet in 14 miles from Warrington to 

 Anderson. 



E SKIERS. 

 RAUB ESKER AND ESKER TROUGH. 



A depression about one-hslf mile in width and 20 to 30 feet in depth leads from the edge of 

 the low plain at Raub southwestward up Little Wea Creek past the Linden-Darlington bowlder 

 belt. It narrows sharply on entering the moraine outside the bowlder belt, and is traceable 

 across the moraine to Shawnee Creek only through narrow sags scarcely 100 yards wide winding 

 among the knolls. Evidence to support the view that a lake had been held between the retreat- 

 ing ice border and this divide was not discovered. What little channeling has been done at the 

 divide was probably accomplished by streams issuing from the ice sheet when it stood at or near 

 the edge of the moraine. The broad depression along Little Wea Creek is occupied by an esker 

 which terminates at the Linden-Darlington bowlder belt, and it seems to have been developed in 

 advance of the esker, as is usual in esker troughs. 



The esker heads on the low plain 1^ miles northeast of Raub, in the south part of sec. 29, 

 T. 22 N., R. 4 W., and is developed as a small but practically continuous ridge 8 to 10 feet 

 high and 50 to 60 yards wide as far as Raub, where it strikes the south bluff of the channel or 

 depression above described just east of the railroad station and is deflected northwestward about 

 150 yards but there turns back to its southwestward course and leads up the channel. It is 

 interrupted in places for the first mile beyond Raub, but from there on it is nearly continuous for 

 about 2 miles to sec. 10, T. 21 N., R. 5 W, where it attains its greatest height of about 40 feet. 

 It enters the Linden-Darlington bowlder belt in sec. 10, and has only a weak development in the 

 form of low knolls in this and adjoining sections on the south and west. One of these knolls 

 near the southwest end of the esker is cut by the wagon road on line of sees. 9 and 10 and shows 

 some till with a poorly assorted sandy gravel. The esker so far as opened elsewhere appears to 

 be composed of gravel of medium coarseness and much better assortment than in this exposure. 

 In Indiana and neighboring States the writer has found a few other occurrences of till with the 

 assorted material at the morainal end of an esker. No esker fan or sand plain exists at the 

 southwest end of the esker unless it be below the bed of the channel in which the esker lies. 

 The esker seems to be on a slight upgrade from Raub to its southwest terminus, the altitude of 



