Part III. A Study of the Stylolites of the Indiana 

 Limestones and the Conclusive Evidence of 

 Their Origin by Chemical Solution 



The field investigations of the writer have been confined, 

 for the most part, to the rocks of southern Indiana. A few 

 observations, however, have been made also in the Niagaran 

 and Onondaga limestones of Xew York, in the Monroe and 

 Columbus limestones of Ohio, and in the Tennessee marbles. 



GEOLOCxIC DISTRIBUTION OF STYLOLITES IX 

 INDIANA 



In Indiana, the stylolites of special significance are found 

 in the thick ^Middle Mississippian limestones of three ages : 

 namely, the Harrodsburg, Salem (otherwise known as the 

 Spergen. and commercially knovm as the Bedford, or Indiana 

 Oolitic), and Mitchell. Brief descriptions of these three 

 formations follow: 



Harrodsburg Limestone 



This is the lowest of the three above-mentioned forma- 

 tions and lies between the Knobstone (a series of alternating 

 arenaceous shales, and sandstones) below, and the Salem 

 limestone above. The formation varies in thickness from 60 

 to 90 feet. It is generahy impure : and in places, is dolomitic. 

 In its lower part, it is a very coarse crinoidal limestone; near 

 the central part, it becomes finer. Here the crinoids, large 

 brachiopods. and pelecypods are replaced principally by bry- 

 ozoans. Near the top, the limestone assumes very much the 

 character of the overlying Salem. ^ 



Salem Limestone 



■ No limestone in the Lhiited States is better known nor 

 more valuable for ornamental and building pui-poses than the 

 Salem limestone.' It occurs in massive beds varying in thick- 



1 For a complete description of the Harrodsburg limestone, reference should be made 

 to: Beede. J.W.. 1915. pp. 194-203. 



-For the latest full discussion of the Salem limestone, reference should be made to: 

 Blatchley, R.S., 190S, pp. 299-460. 



6—22663 (35) 



