Additions to the flora of the Spotted Ridge Formation in central Oregon Mamay, Sergius H. 1920- creator author. Read, C. B. author. Geological Survey (U.S.) issuing body. text bibliography dcu 1956 monographic eng remote 1 online resource (22 unnumbered pages, 4 unnumbered pages of plates) : illustrations. by Sergius H. Mamay and Charles B. Read. "The U.S. Geological Survey' s previously undescribed collection of fossil plants from the Spotted Ridge formation is fully described and illustrated, including three new species." Includes bibliographical references (pages 223-224) and index. n-us-or From 280 to 310 million years ago fast Paleobotany Oregon, Central Paleobotany Pennsylvanian Formations (Geology) Oregon, Central Paleobotany Pennsylvanian Geologic Period Oregon, Central I 19.16:274-I I 19.16:274-I Additions to the flora of the Spotted Ridge Formation in central Oregon Mamay, Sergius H., 1920-. (OCoLC)2696433 Geological Survey professional paper ; 274-L Shorter contributions to general geology https://purl.fdlp.gov/GPO/gpo86141 OCLCE 101209 20211120182637.0 in00003972600 eng