The Pennsylvanian No. 5 Block coal bed in eastern Kentucky is one of several coals considered to be among the splint coals of the Central Appalachians. The coals are generally noted for their inertinite-rich dull lithotypes. Petrographic aspects of the lithologies reveal both fire-derived and degradation-derived inertinites in the assemblages. Fire is not an exclusive contributor to the origin to inertinite macerals; there are many other biological factors, such as the actions and interactions of fungi, bacteria, and insects, which must be considered in the alteration of plant materials to form inertinite macerals. Fungi physically and chemically alter plant tissues to form macerals with a distinct morphology and chemistry different than those formed from fire and other abiological processes. Insects, as secondary sources of wood degradation within a mire, are responsible for physical, such as boreholes from wood-consuming insects, and chemical alteration of plants. Degradation observed in macrinite may be boreholes from wood-consuming insects such as mites. Some inertinite macerals, in particular, macrinite, may be the result of inert fecal pellet conglomerates preserved in the mire. Overall, macerals of the same name can form from multiple and complex biological and abiological processes. (C) 2012 Elsevier B.V. All rights reserved.