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INDIANA UNIVERSITY STUDIES 



rough, the steep slopes being the result of the predominating lime- 

 stones, and is somewhat in contrast to the rounded hills of the 

 Eastern Highland of southeastern Indiana. The general slope 

 is to the west. The eastern rim of the Clinton and the Niagara 

 is the dividing line between the White River and Whitewater River 

 systems. The streams flow southwest down the dip of the rocks 

 and the Niagara is exposed in the bed of the streams for several 

 miles to the west of the general outcrop. 



Devonian. The Devonian rocks succeed the Silurian, and may 

 be grouped into two main divisions, the lower being limestones 

 and the upper soft shales. The most important limestone is the 

 Corniferious, or Jeffersonville, which is a rather hard bluish gray 

 limestone, the combined strata averaging about sixty-five feet in 

 thickness. To the north it seems to be partly replaced by the 

 Geneva, a buff or brownish colored magnesian limestone. Above 

 the Jeffersonville limestone, are two thin beds of limestone known 

 as the Silver Creek and the Sellersburg. These outcrop in the 

 extreme northern part of the region. On top of these limestones 

 occur the New Albany Black Shales, which will average 125 feet 

 in thickness. These shales are sulphurous and contain so much 

 bitumen that they will burn when thrown on a fire. Weathering 

 takes place very rapidly in these shales and as a result the region 

 is worn down almost to base level. This region about New Albany, 

 Scottsburg, Seymour, Columbus, and Franklin averages about 

 10 to 15 miles in width, and is known as the Eastern Lowland. 

 It is from 500 to 700 feet above the sea. The East Fork of White 

 River flows southward through this trough for many miles to Rock- 

 ford in Jackson County, where it turns to the southwest, and flows 

 through a gorge in the succeeding formations. 



Mississippian. The Mississippian strata, in Indiana, occupy 

 the middle portion of the southern half of the State, and next to 

 the P.ennsylvanian, are the most important rocks in the State. 

 The Mississippian in Indiana is divided into six divisions, which 

 aggregate over a thousand feet in thickness. These divisions will 

 be treated in the order in which they occur, beginning with the Goni- 

 atite limestone, which is the oldest. The Goniatite limestone is 

 unimportant, but is remarkable in its consistency in underlying 

 the whole Mississippian system. It is generally less than six feet 

 in thickness. The Knobstone group is composed of shale at the 

 bottom, while near the middle are massive dark blue calcareous 

 and clayey sandstones, and near the top is a light brownish sand- 



