Martin, Helen M. 1889-1973. An index of the geology of Michigan, 1823-1955. - [Lansing, Speaker-Hines & Thomas, State printers, 1956] - ix, 461 p. maps (part fold.) fold. charts (in separate envelope) 24 cm. - Michigan. Geological Survey Division. Publication 50. . LCCN: gs 57000152 Subjects--Corporate Names: Michigan. Geological Survey Division --Bibliography. Subjects--Topical Terms: Geology--Bibliography.--Michigan LC Class. No.: Z6034.U5 / M63