Shale gas has been produced in the area since 1883, when H.A. Mastick's well was drilled in the Rockport Township to a depth of , yielding of gas daily. A gas boom occurred in 1914–1915, and by 1931, several hundred gas wells were producing from the Devonian Huron shale. Production came from shales thick at depths from . Pressures were flowing less than of gas daily, but was sufficient to furnish light for a house or two, and sometimes heat. As Cushing et al. pointed out in the 1930s, "there are vast amounts of petroleum in the Devonian shales." Since then, the Marcellus Shale and the deeper Utica Shale have shown their economic potential.