A CENTURY OF GEOLOGY IN INDIANA. 101 



south-eastern Indiana," the blue Umestone with its associate beds of marlites 

 and mudstone." This he correlated with the Lower Silurian, as the lowest 

 Geological formation in Indiana. 



We thus see that in this first cross section of southern Indiana, Dr. Owen 

 recognized all the principal formations which we now retain, though some of 

 them, as the Subcarboniferous and the Devonian, have been subdivided by 

 more recent geologists. 



After completing the line across the southern edge of the State, Dr. 

 Owen ran a number of what he calls zigzag lines south of the National Road 

 to determine the limits in the southern part of the State of the various 

 formations above mentioned. As a result of these lines he located approxi- 

 mately yet fairly accurately the eastern limits of the coal area, stating 

 that "from Oil Creek, Perry County, the line of junction between the coal 

 formation and underlying subcarboniferous limestone runs pretty nearly 

 north, a little west of Paoli, Bedford and Bloomington, thence it bears some- 

 what more to the west near Spencer, and crosses the National Road near 

 Putnamville." 



"It will therefore be a useless waste of time, money and labor to search 

 for coal in any of the counties east of the second principal meridian, or east 

 of the belt of limestones, that succeed to the coal formation on the east; 

 because all experience goes to show that there are no workable beds of coal 

 associated wth these limestones, or any of the underlying formations, that 

 crop out to the surface east of that formation. Therefore, all search for coal 

 in or beneath the black slate formation of Floyd, Clarke, Scott, Jackson, Bar- 

 tholomew, Johnson and Marion Counties may be predicted as fruitless." This 

 statement he also reiterates on page 57 of his second report, and time has 

 proven the truth of his assertions. 



From these zigzag lines he also outlined very accurately the approximate 

 areas over which each of the formations above named constitute the surface 

 rocks. For example, he states that the black aluminous slate (now known as 

 the New Albany or Genesee shale) "extends through a great part of Clarke, 

 Scott, Jennings, Jackson, Bartholomew, Shelby, Johnson and Marion Coun- 

 ties, towards Indianapolis ; but in this neighborhood near the National Road, 

 the strata are so completely covered by drift, that it is difficult to detect the 

 original strata. Even the deepest wells have not penetrated through this 

 drift." 



In the fall of 1837, Dr. Owen continued his reconnaissance north of the 

 National Road, where he "foimd the greater part of this northern country 

 covered by a drift of sand, gravel, boulders and clay, sometimes to a very 

 great depth." For this reason he found it difficult to locate outcrops and de- 

 termine the formations, though he records, and correctly, that the eastern 

 boundary of the coal formation crosses the Wabash near Attica and that the 

 counties of Parke, Vermillion and parts of Warren and Fountain belong to 

 that formation. He visited the border of Lake Michigan and mentions the 



