RECENT WORK IN THE COAL EIELD OF INDIANA AND ILLINOIS. 
By Myron L. Fuller and George H. Ashley 
INTRODUCTION. 
The coal investigations recently conducted by the United States 
Geological Survey in the States of Indiana and Illinois were limited to 
the southern portions of the two States, the areas covered being 
included in two adjacent thirty-minute quadrangles. The easterly 
one, known as the Ditney, embraces portions of Pike, Gibson, Van- 
derburg, Warrick, Spencer, and Dubois counties of Indiana, and the 
westerly quadrangle, known as the Patoka, includes the remaining 
parts of Gibson and Vanderburg counties, portions of Posey and Knox 
counties in Indiana, and of Wabash, Edwards, and White counties in 
Illinois. The combined area of the two quadrangles is 1,872 square 
miles. 
The investigations in the Ditney quadrangle were prosecuted in 
1900 and 1901, and the results have already appeared in the form of 
a geologic folio, a in which are given, in addition to the descriptions, 
maps showing the outcrops of the geologic formations, contours show- 
ing the approximate depth of the principal coal, and a large number 
of sections showing the thickness, character, and structural relations 
of the coals. The investigations in the Patoka quadrangle were pros- 
ecuted in the latter part of 1902, and the results will be prepared and 
published in the same form as those relating to the Ditney quadrangle. 
COALS OF THE DITNEY QUADRANGLE. 
Five or more beds of this quadrangle are of sufficient thickness to 
warrant development, at least for local' supplies, but only one of the 
beds, the Petersburg coal, is worked for purposes of shipment. The 
other veins, however, especially the Millersburg coal, are extensively 
mined in the fall and winter months to supply local demands. The 
coals vary greatly in thickness at different points, and all of them 
show marked and sudden changes, due to their accumulation, it is 
believed, in basins of variable depth, or in series of basins that were 
only partially connected or even completely separated. The coals 
above the Millersburg are few in number, are usually under a foot 
in thickness, and, except in rare instances, are not workable even for 
local purposes. 
« Geologic Atlas U. S., folio 84, Ditney, Ind. 
284 
