This paper reports that coalbeds are generally thin and discontinuous in Late Devonian and Early Mississippian Pocono Group strata of Pennsylvania and Maryland. Three types of coals, based upon the environment of formation, are recognized. Transgressive coals predominate within the Rockwell Formation in western Maryland and south-central Pennsylvania. These coalbeds are exceedingly thin (1 to 10 cm), often exhibit thin underclays, and are overlain by Skolithos- or brachiopod-bearing sandstones. Less frequently, thin regressive coalbeds cap the top of individual transgressive-regressive packages. These coalbeds average 1 to 3 cm in thickness and do not have underclays present. Higher in the section, coals are also present between sandstone bodies of the Burgoon (Purslane) Formation. These coalbeds are typically thicker than those of the Rockwell, but, owing to channel migration in the associated sandstones, are commonly discontinuous. Such coalbeds are swamp deposits which developed lateral to migrating channels.