178 



irregularly. In tho belt of thick drift wliiili Ic.-uls from Ronton Countj' 

 southeast to Marion County, and thence east into Ohio, the thickness is 

 probably 200 feet. The jmrtiou of the newer drift area to the south of 

 this belt has an averajie of about titty to seventy-five feet. A still larjjer 

 tract extending north from this belt of thick drift as far as Allen County 

 and the west tlowine; portion of the Wabash, has only fifty to seventj'- 

 (ive feet, with limited areas where its thickness is Imt twenty to tliirty 

 feet. In northwestern White, southwestern Pulaski, and southern Jasper 

 counties there are several townships in which scarcely any drift api>ears 

 excepting boulders and sandy deposits. In northern Indiana the drift is 

 very thick. Its average thickness for fifty miles south of the north 

 lioundary of the State is probably not less than 2r>0 feet and may exceed 

 nOO feet. At Kendallville it is 4S5 feet, and at several cities on the 

 moraine which leads northeast from Fulton County to Steuben County, its 

 thickness has been shown by gas borings to exceed 3(X) feet. The rock 

 is seldom reached in that region at less than 200 feet. Were the drift 

 to be strlpjjed from the northern portion of Indiana its altitude would be 

 about as low as the surface of Lake Michigan, though much of the present 

 surface is 200 to 300 feet above the lake"'' 



TOPOGRAPHY. 

 The surface of Indiana jiresents no great diversity of t>)pograi)hic 

 I'eatures. The eli'vation above sea level ranges from 313 feet at the junc- 

 tion of the Ohio and Wabasli rivers to about 1,2^") feet, in tlie southern 

 I)art of Kando'iili County. It is on this height of land that both the 

 east and west forks of White iliver liave their source. The average 

 elevation of the State is about T(t<> feet. The greater part of the Stjite is a 

 plain of accumulation. North of the glacial boundary much of the area 

 has a comparatively level surface, or only gently undulating. In the 

 northeastern ]iart of the State are .some considerable hills and ridges, 

 formed from the coarser materials and large Ixiulders of the drift. These 

 morainic ridges, some of which reach a height of 2W feet, stand out in 

 sharp contrast to the level area of old Lake Mauniee on the south, and 

 to the sand covered area to I he west. Here on the west, the Kankakee 

 Marsh with an area of l,(i<i(t s(|u:n-c miles is ver\- Hat. and the area to 



'See U. S. G. S. Mono^rapli XXWIII. I.cvcr.ll. .Msu "Studi. 

 flcopraphy," Dryor, pp. 20-40. 



