CHAPTER VI. 



CORRELATIVES OF THE BLOOMINGTON MORAINIC SYSTEM. 



By Frank Leverett. 



INTERPRETATION . 



The system of moraines to which the name Bloomington is applied is one of the largest 

 developed by the Illinois lobe. It receives its name from the city of Bloomington, 111., which 

 stands on a prominent portion of the outermost ridge of the system. Where best developed, 

 in eastern Illinois and western Indiana, it consists of four bulky ridges, but west of Illinois 

 River these are merged into a bulky outer ridge and a small inner ridge. This system of 

 moraines has been discussed in Monograph XXXVIII throughout the length of the portion 

 developed by the Illinois lobe. It remains to consider the equivalent of this system produced 

 in Indiana by the Huron-Erie portion of the Labrador ice field. 



A massive accumulation of drift running across central Indiana from west to east was 

 brought to notice and briefly discussed by Maurice Thompson as a "Terminal moraine in 

 central Indiana." 1 Thompson recognized the complexity of this belt, for after outlining its 

 course he remarked: 



I have for mere convenience called the morainic mass thus roughly outlined a terminal moraine; but I regard it a 

 cluster or tangle of a number of inseparable moraines, caused chiefly by the separating of the great glacier into lobes 

 and by successive advances and retreats of the ice mass. 



COURSE AND DISTRIBUTION. 



From the eastern end of the ridges of the Bloomington system, at the reentrant angle in 

 Benton and Warren counties, Ind., the belt of thick drift leads southeastward across Tippecanoe 

 and northern Montgomery, Clinton, and Boone counties into the edge of Tipton County. It 

 there swings southward and passes through southwestern Tipton and western Hamilton and 

 Marion counties, past the city of Indianapolis, its outer part extending into northern Johnson 

 County. From Marion County it runs eastward across Hancock, southeastern Madison, 

 western and northern Henry, southeastern Delaware, southern Randolph, and northern Wayne 

 counties into Ohio. In Randolph and Wayne counties it connects with the " main morainic 

 system" of the Miami lobe discussed in Monograph XLI. In the present report only the part 

 in Indiana will be discussed. 



TOPOGRAPHY. 

 ALTITUDE. 



This great drift belt includes the most elevated pomts in Indiana, which are near the east 

 line of the State in Randolph and Wayne counties and reach 1,250 to 1,285 feet. The lowest 

 parts are on the border of White River near Indianapolis, where the altitude is about 725 feet, 

 and on the border of the Wabash below Lafayette, where it falls slightly below 700 feet. The 

 descent of 500 feet, which the moraine makes from near the Indiana-Ohio line to the White 

 River valley near Indianapolis,, is very gradual, the distance being about 70 miles. Between 

 the White and Wabash valleys there is a rise of about 250 feet, or to nearly 1,000 feet. At the 

 reentrant angle west of the Wabash the altitude reaches 850 to 875 feet at the highest points on 

 the ridges near Fowler, but on the plains between the ridges it is scarcely 800 feet. 



1 Fifteenth Ann. Rept. Indiana Dept. Geology and Nat. Hist., 1886, pp. 57-60. 



