"Marine faunas of the Devonian tree horizons of Tygart Valley, West Virginia."; "Tilton, John Littlefield, b. 1863."; "Geology, Stratigraphic--Devonian.", "Geology--West Virginia--Tygart Valley."; "Tilton, John Littlefield, b. 1863."; "1929"; "Journal article reprint from: American Journal of Science, v.17 (1929:Apr.). "; ""; "P1186"; "pec"; "Geology, Stratigraphic--Devonian.", "Geology--West Virginia--Tygart Valley."; "14256"; .