. 
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 aré 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 aikeicnn: 
The “black or bituminous slate,” which begins at Floyd coun- 
ty, one hundred and four feet thick, passes up through Clark, 1s 
seen at Delphi onthe Wabash, and is the next rock in the ascend- 
ing order. A series of sandstones, limestones, clays, sbales, bitu- 
minous coal, and argillaceous iron ores—in fact, a regular bitumin- 
ous coal Sonietitie: 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 Chio, where the second principa 
meridian crosses it, it passes three miles east of the line, betwee? 
Martin and iawnoce counties; crosses the National Road one 
or two miles west of Putnamvilis: crosses the Upper Wabash 
near Independence, thence neahwie 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.” 
