Permian sphenopsids from Antarctica Rigby, J. F. creator author. Geological Survey (U.S.) issuing body. text bibliography dcu 1969 monographic eng remote 1 online resource : illustrations. by J. F. Rigby. Title from title screen (viewed September 24, 2014). "Descriptions and distributions of species of the fossil plant genera Phyllotheca, Schizoneura, Paracalamites, and Umbellaphyllites." Includes bibliographical references (pages F11-F12) and index. t------ Paleobotany Permian Paleobotany Antarctica Sphenopsida, Fossil Antarctica Paleobotany Permian Geologic Period Sphenopsida, Fossil Antarctica From 230 to 280 million years ago fast I 19.16:613-F I 19.16:613-F Permian sphenopsids from Antarctica Rigby, J. F. (DLC) 79606680 (OCoLC)82451 Geological Survey professional paper ; 613-F Geological Survey professional paper Contributions to paleontology https://purl.fdlp.gov/GPO/gpo82759 COP 140929 20211120182454.0 in00003862727 eng