Type locality, reference section, and use of name: The Hymera Coal Member of the Dugger Formation was proposed by Wier (1961, 1965) in an unpublished manuscript for exposures near Hymera, Sullivan County, Ind., but was first published by Wier and Powell (1967). Natural exposures near Hymera are rare because of stripping operations, but Wier designated a reference section in the NE¼NW¼NE¼ sec. 10, T. 8 N., R. 8 W. In Sullivan County this unit had previously been designated as Coal VI (Ashley, 1899, p. 839-915; 1909, p. 56).
Description: The Hymera Coal Member is a bright-banded coal, which ranges from 0.5 to 11.0 feet (0.2 to 3.4 m) in thickness. The coal contains numerous small shale-and-pyrite partings two of them, lying in the upper part of the coal, can be traced throughout Sullivan County and northern Knox County. In northwestern Knox County one shale-and-pyrite parting thickens, so that the coal is split into two benches. The Hymera coal, which contains a characteristic spore content composed almost entirely of the genera Laevigatosporites and Lycospora (Guennel, 1952, p. 29), is overlain in most places by a dark-gray to gray silty shale or fine-grained sandstone.
The Hymera Coal Member is traceable from its type area southward to southern Knox County and northward to southern Vigo County. It is not present in northern Vigo County or in Vermillion County. It thins abruptly in southern Knox County but is present in Gibson, Pike, and Warrick Counties, where it has been called the Lower Millersburg Coal. (See Wier, 1961, 1965.)
Correlation: The Hymera is probably correlative with the Jamestown Coal Member in southern Illinois and with the Paradise Coal (W. Ky. No. 12) in Kentucky.