55 



From the east border of the river, a few miles below Columbus, northeast- 

 ward to Wliitewater valley, in southern Fayette County, there is a well- 

 defined ridging of drift standing twenty to forty feet above the border 

 tracts. Upon crossing Whitewater, the border leads southeastward and is 

 not so well defined as west of the river, though there is usually a ridge 

 about twenty feet high. 



From the north line of Jackson County, following the boundary around 

 to the west and south, it is in many places hai'd to trace as a well-defined 

 line. The ice-sheet nuist have been very thin, since the topography shows 

 little, if any, modification. In many places, however, heavy beds of gravel 

 and till lie against the hill slopes to the north and east. Many largo 

 granite bowlders are also piled up along the hillsides and scattered along 

 the streams. In this area in the counties of Hendricks, Rush. .Johnson, 

 Shelby, Henry, Decatur and lJandol])h, there is a form of moraine known 

 as "bowlder belts," long, narrow, curving strips of country, thickly cov- 

 ered with large bowlders. Low, winding ridges of sand and gravel parallel 

 to the ice movement mark the course of a sub-glacial drainage through 

 Madison, Hancock. Shelby and Bartholomew counties. The longest glacial 

 drainage channel in the State extends from Grant County to White River, 

 in Bartholomew, but it is not now occupied by any one continuous stream. 

 Most of the streams in the glacial ai'ea are known as sand and gravel 

 streams and afford great quantities of sand of economic importance and 

 an abundance of gravel suitable for road material and ballast. In several 

 of the counties are overwash aprons in which the sand and gravel are 

 spread out over broad areas. 



The thickness of the drift over the State varies greatly, the greatest 

 thickness in the State being about 500 feet. AVhile in this area the drift 

 would be from 50 to 100 feet, there is on the higher points but a thin coat- 

 ing, but the filled valleys make a higher average. It is the glaciated part 

 of the area that is of importance from an agricultural standpoint. The 

 glacial drift is a very productive and permanent soil, and can not be sur- 

 passed in the production of the cereals, while the bluffs, knobs and hills 

 of the driftless area are proving to be favorable for the growing of fruits. 



The rocks of the State are all sedimentary, and in the area here dis- 

 cussed were laid down upon the bed of a shallow sea receding to the south- 

 west. Thus the strata dip gently to the southwest, at the rate of about 20 

 to 40 feet to the mile. 



In the State there ai"e six different geological periods rei)resented — the 



