Carboniferous successions may have hydrocarbon source‐rock potential in several districts of Northern Ireland. They have been buried to depths required for hydrocarbon generation beneath younger Carboniferous rocks in the west, and beneath Permo‐Triassic basins in the east. Samples of coals and shales collected from outcrop and boreholes have been less‐deeply buried and are consequently less mature, but upon pyrolysis give good hydrocarbon yielak, which suggests that hydrocarbon generation is likely to have occurred in the basinal districts. Carboniferous rocks in the west, and in adjacent parts of the Republic of Ireland, include numerous shows of solid bitumen, which represent degraded oil residues. However, the coaly nature of much of the carbonaceous sediment suggests that the predominant hydrocarbon product would probably b