A preliminary investigation was conducted to find fossil fuel resources, other than tar sands and heavy oil deposits, that are suitably associated with coal for potential application of underground coal gasification (UCG) technology to provide heat for production of liquid hydrocarbons. Preliminary evaluations of UCG applications for in situ retorting of oil shale and for thermal enhanced oil recovery (EOR) from abandoned oil fields indicate large areas where deposits may be suitably associated. Major resources of Devonian-Mississippian black shales and Carboniferous coal occur in the same regions in the Appalachian Basin, Michigan Basin, Eastern Interior Basin (Illinois Basin), and possibly in eastern Oklahoma. Possibilities for UCG applications to Green River oil shales are limited to a few localities on the flanks of the Rock Springs uplift and Wamsutter arch in Wyoming and on the west edge of the Piceance Basin in Colorado. Because conventional primary and secondary oil recovery processes leave 30% to 60% of the oil in the ground, all oil fields that are suitable for thermal EOR processes and are close enough to coal deposits are potential candidates for use of UCG combustible gas and sensible heat. Such relationships are likely to occur in any of the major coal-bearing regions of the eastern United States and in many of the sedimentary basins of the Rocky Mountain coal province. Oil fields and lignite deposits may occur close together in the Gulf Coastal Plains and northern Great Plains. 19 refs., 2 figs.