A GEOLOGICAL SECTION ACROSS SOUTHERN INDI- 

 ANA, FROM HANOVER TO VINCENNES. 



INTRODUCTION. 



During the field season of 1896 the Indiana University Geo- 

 logical Survey undertook to map, geologically and topographic- 

 ally, a section across southern Indiana, reaching from the Ohio 

 River at Hanover on the east, to the Wabash River at Vincennes 

 on the west. The strip of country mapped is 6 miles wide, 

 120 miles long, and is embraced in the row of townships num- 

 bered 3 north. 



METHOD OF RUNNING THE SECTION. 



The topographic work was done by means of aneroid barom- 

 eters, with a line of levels through the territory by which the 

 aneroid readings were checked. This line was run as far as 

 Willow Valley station in Martin county, and as near the middle 

 of the strip of country to be mapped as the conditions would 

 permit; the elevations were obtained by means of the vertical 

 arc, and are as accurate as the necessities of ordinary topogra- 

 phy and geological cross sections demand. The line of levels 

 was checked on the J. M. & I. and the B. & O. S.-W. R. R., 

 where these roads were crossed. The dips of strata as shown by 

 these levels may be depended upon within the suggested limits. 



The section chosen was selected because the geological hori- 

 zons and the topography crossed by it are typical of almost the 

 entire southern part of the state. The geological horizons can- 

 not be taken up here in detail, but it is desired to point out some 

 of the relations existing between the topography and the geology. 



THE HORIZONS CROSSED AND THE RESULTING TOPOGRAPHY. 



The eastern plateau. — Beginning in the east near Hanover, at 

 the west side of township 3 north 10 east, the lowest rocks 



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