According to this U.S. Bureau of Mines study, the Hartshorne Formation of the Arkoma Basin contains a complex association of gas reservoirs and possible source rocks. Geological and geochemical data suggest possible solutions to problems concerning the generation, migration, and retention of gases within the formation. The close association of the Hartshorne coalbeds and sandstones complicates an understanding of the origin and subsequent migration of the gas. Possible source rocks are the Hartshorne coalbed, the marine atoka shales below, and the carbonaceous McAlester shales above the Hartshorne Formation. Coalbed gas sampled from a mine near the quinton field contained more methane and less ethane, propane, and butane than natural gas from the quinton field. This may be due to the high sorption properties of coal. The heavier hydrocarbon gases remain adsorbed on the surface of the coalbed micropore structures, with higher proportions of methane released into coalbed macropore structures. Data collected so far indicate that the gas from the poteau-gilmore and camaron fields is derived, at least partially, from associated coalbeds, while the gas from the quinton field may have another origin.