Shows oil and gas wells. "Structure contours above sea level showing coal V or its position before erosion."--Legend. Detached from: The Oakland City, Indiana, oil field in 1910 / Ralph F. Blatchley. In Indiana Dept. of Geology and Natural Resources thirty-fifth annual report, 1910. Indianapolis: Wm. B. Burford, 1911. Page 79. Imprint: [Indianapolis] : [Indiana Dept. of Geology and Natural Resources], [1911] Dimensions: 57 x 40 cm