Figure 6 - Atomic H/C vs. O/C for lithotypes of the Pennsylvanian Breckenridge torbanite (solid circles); density-gradient-centrifuge-derived separates of the Devonian Cleveland member of the Ohio shale (numbered in order of increasing density); and whole channel and bench samples of the Western Kentucky No. 9 (Springfield) and Western Kentucky No, 11 (Herrin) coals (solid squares). All samples are from Kentucky.