134 Notice of Geological Surveys. 



cessary. The portion of the state north of the National Road, is 

 covered by a deep deposit of diluvium, and the channels of the 

 streams only afforded opportunities for studying the rocks. 



The east and north portions have the same geology as the 

 neighboring part of Ohio. The "blue limestone" is the lowest 

 and oldest rock in Indiana, and alternates with clays and marls, as in 

 Ohio. It retains its highly fossiliferous character, and in this par- 

 ticular Dr. Owen thinks it greatly resembles " the mountain 

 limestone" of Europe ; of course, for want of the evidence, no 

 one else can have an opinion, except to refer to that of Mr. Con- 

 rad. This forms a dividing ridge between the waters running 

 into the Wabash and Ohio, in the southeast counties of Switzer- 

 land, Dearborn, Franklin, Union, and Fayette ; it forms the east- 

 ern boundary of the cliff stratum, and it is found that below Union 

 county, certainly, the cliff strata of the two states are not con- 

 tinuous. It occupies the elevated ridges in Jefferson, Ripley, 

 Decatur, and Rush, and the eastern part of Scott, Jennings, and 

 Shelby counties ; and from Elkhorn, Wayne county, to Fall creek, 

 in Fayette county, the "cliffs" of the two states are separated 

 by an interval of eighteen or twenty miles, and they are the prev- 

 alent rock in the northeast, under the diluvium. 



The " black or bituminous slate," which begins at Floyd coun- 

 ty, one hundred and four feet thick, passes up through Clark, is 

 seen at Delphi on the Wabash, and is the next rock in the ascend- 

 ing order. A series of sandstones, limestones, clays, shales, bitu- 

 minous coal, and argillaceous iron ores — in fact, a regular bitumin- 

 ous coal formation, distinct from the Ohio and Michigan basins, 

 succeeds these carboniferous deposits — and constitutes the latest 

 rocks that have yet been observed in the state. Dr. Owen re- 

 marks : — " Our bituminous coal formation is part of a great coal- 

 field, which includes nearly the whole of Iowa, Illinois, and eight 

 or ten counties in the northwest part of Kentucky. It occupies in 

 Indiana an area of about seven thousand seven hundred and eighty 

 square miles — beginning on the Ohio, where the second principal 

 meridian crosses it, it passes three miles east of the line, between 

 Martin and Lawrence counties ; crosses the National Road one 

 or two miles west of Putnamville ; crosses the Upper Wabash 

 near Independence, thence northwest into Illinois to the mouth of 

 the Kankakee." This coal resembles very much that of Meigs 

 county, Ohio, exhibiting " spots and regular layers of absolute 

 charcoal from which the woody fibre can be detached," 



