Paleoenvironments favorable for lignite deposition existed in sedimentary regimes of the Naheola Formation (upper Midway Group) and in Midway-Wilcox transition sediments apparently assignable to the Nanafalia Formation (Wilcox Group). In addition, lignite horizons are recognized in the Tuscahoma Sand (Wilcox Group). Lignite of potential economic significance occurs within the Naheola Formation west of Butler County and within the Nanafalia Formation east of Butler County. Lignite horizons in the Naheola Formation west of Butler County probably are not stratigraphically or time equivalent to lignite horizons east of Butler County. Depositional environments of the Naheola west of Butler County were favorable for development of lignite deposits with extensive lateral continu ty, whereas lignite depositional environments east of Butler County apparently favored variability in thickness and lateral continuity. Estuarine and back-barrier coastal marsh environments are suggested for the lignite.

Carbonaceous silt and clay in varying proportions are commonly associated with lignite in the Naheola Formation. Lithologic associations of lignite related to the Nanafalia Formation include quartzarenite, carbonaceous silt and clay, oyster beds, and limestone of the Clayton Formation (Midway Group).

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