"The Address by the President of the Academy: the trend of geologic thought."; "Tilton, John Littlefield, b. 1863."; "Geology--Addresses, essays, lectures."; "Tilton, John Littlefield, b. 1863."; "undated"; "Journal article reprint from: Proceedings of the West Virginia Academy of Science."; ""; "P1176"; "pec"; "Geology--Addresses, essays, lectures."; "14256"; .