The Helderberg group from central Pennsylvania to southwestern Virginia
By: by Frank McKim Swartz ...
Series: Bulletin (Pennsylvania State University. Mineral Industries Experiment Station) ;; no. 4
Publisher: State College, Pa., School of mineral industries
Published: 1929
Language: eng
Number of pages: 14
Subjects: Paleontology -- United States.; Paleontology -- Devonian.
Notes: Contains references.
[pt. 1] "reprinted from the Proceedings of the Pennsylvania academy of science, v. 3, 1929."