01189cam a22002891i 4500 gs 39000291 DLC 20260227111345.0 830301s1939 paua b s000 0 eng c gs 39000291 (OCoLC)9267463 U.S. Geol. Survey. Libr OAU OCoLC DLC QE665 .P42 1939 Pennsylvania. Bureau of Topographic and Geologic Survey. The Devonian of Pennsylvania : Middle and upper Devonian / by Bradford Willard; Keyser limestone and Helderberg group, by Frank M. Swartz; Oriskany group, by Arthur B. Cleaves. Harrisburg, Pa. : Dept. of internatl affairs, Topographic and geologic survey, 1939. xii, 481 p. : ill. ; 24 cm. Bulletin G ; 19 At head of title: Pennsylvania Geological Survey, Fourth series. Bibliography: p. 434-445. Geology, Stratigraphic Devonian. Geology Pennsylvania. Paleontology Devonian. Willard, Bradford, 1894- Swartz, Frank M. (Frank McKim), 1899- Cleaves, Arthur B. (Arthur Bailey), 1905- 27585 27585