Type section and use of name in Indiana: The name Herrin, taken from Herrin, Wiliamson County, Ill,, where the coal was extensively mined, was first used by Worthen (1870, p. 93) and later by Shaw and Savage (1912, p. 6), who designated the type section in subsurface exposures in mines near Herrin. The name Herrin Coal Member (Dugger Formation) was first proposed for Indiana use by Wier (1961, 1965) in an unpublished manuscript and was first published by Wier (1970).
Description: The Herrin is represented by streaks of coal and thin smut streaks that are found below the Providence Limestone Member along its outcrop in Warrick County. This coal is thin and discontinuous on Indiana outcrop and has not been mined in the state, but it thickens westward in Vanderburgh and Posey Counties, where it ranges from 2 to more than 5 feet (0.6 to 1.5 m) in thickness. It is a bright-banded coal that contains clay or shale partings. A prominent parting (the blue band) occurs in the lower part of the coal where the coal reaches mixable thickness. Florally, the Herrin is dominated by Lycospora granulata; Laevigatosporites minutes is subordinate (Jacobson and others, 1985).
Correlation: Early correlations of the Herrin coal in Illinois and Indiana with the Herrin Coal Bed of Kentucky (W. Ky. No. 11) have been confirmed by Jacobson and others (1985).