ruLLEit and ashlky.] COAL FIELDS OF INDIANA AND ILLINOIS. 285 
MILLERSBURG COAL. 
Because of the covering of glacial drift and of certain confusing 
associations there is not that certainty in the tracing of this bed that 
characterizes the tracing of the more prominent Petersburg coal, but 
what appears to be a single bed, or at least a bed of a closely equiva- 
lent horizon, has been traced in the area under discussion from near 
Chandler on the south to Petersburg on the north, the outcrop passing 
near Lynville, Oakland City, Ingleton, Dongola, Glezen, Rumble, and 
Clark. The outcrop is worked by stoppings at over a hundred points, 
the workings being especially numerous along Squaw Creek east of 
Millersburg, south of Lynville, north of Ingleton, on both sides of the 
Patoka River at Dongola, along Robinson Creek, southeast of Rumble, 
and between Rumble and Petersburg. The thickness is generally 
insufficient to warrant shafting, but the coal is worked from shallow 
shafts at Millersburg, east of Elberfeld, and at Union. A shaft is 
now (1902) being sunk to this coal near Buckskin, where the coal is 
reported to reach a thickness of over 6 feet. 
The thickness of the Millersburg coal varies from 2 to 6 feet or 
more, 3 feet probably being a fair average for the area as a whole. 
A number of the more characteristic local measurements are given in 
the table on page 288. 
The interval separating the Millersburg coal from the next lower or 
Petersburg bed is generally from 70 to 90 feet, but if the correlations 
are correct the interval increases to about 100 feet near Ingleton and 
to 120 feet near Oakland City. 
PETERSBURG COAL. 
The outcrop of the Petersburg coal is largely hidden by glacial 
deposits in the northern portion of the quadrangle, but over an area 
beginning near Cato and continuing to the southern border, south of 
Boonville, it has been opened at many points and is worked at short 
intervals. The dip being very gentle, averaging only about 20 feet 
to the mile to the west, and the coal lying at or near drainage level 
over considerable areas, the outcrop partakes of all the sinuosities of 
the drainage lines, its length being several times that of the 
quadrangle. 
The coal is of variable thickness, but probably averages about 5 feet 
in this quadrangle. East and northeast of Boonville, however, its 
average thickness is somewhat greater, being not far from 6 feet, and 
thicknesses of 7 feet are common in many of the mines, while in 
pockets a thickness as high as 9£ feet is reported. In this region it is 
solid and uniform throughout, except that the upper 3 to 6 inches is 
dry, resembling cannel coal in places. Thicknesses of 8 feet occur in 
many of the mines about Petersburg. At other points thicknesses of 
4 to 6 feet are most common. Measurements at a large number of 
points are given in the table on page 289. 
