A GLOSSOPTERIS FLORA FROM THE OHIO RANGE, ANTARCTICA

CRIDLAND, ARTHUR A. (Ohio State U., Columbus.) A Glossopteris flora from the Ohio Range, Antarctica. Amer. Jour. Bot. 50(2): 186-195. Illus. 1963.-Leaves of Glossopteris indica are the commonest fossils in the Mount Glossopteris Formation on Mount Schopf. Other fossils present are: Glossopteris ampla, G. angustifolia, G. damudica, G. browniana, detached scales, sporangia of Arberiella containing bisaccate pollen grains, seeds of Samaropsis (principally S. longii), and some obscure fossils. These remains, and associated animal fossils, suggest that the Mount Glossopteris Formation is Permian. The plants evidently grew in a seasonal but favorable climate. These growth conditions indirectly support paleomagnetic calculations which indicate that in Late Permian time, Mount Schopf lay near latitude 50?S. SCANT but important collections of fossil plants have revealed an Antarctic Glossopteris flora in the Permian part of the Beacon Sandstone and the P'ermian Mount Glossopteris Formation. Fossils already known are: Glossopteris indica (Seward, 1914; Schopf, 1962), cf. G. indica (Edwards, 1928), Dadoxylon sp. (Edwards, 1928), Antarcticoxylon preistleyi (Seward, 1914), cf. A. preistleyi (Schopf, 1962), Samaropsis longii (Schopf, 1962), Vertebraria sp. (Seward, 1914), Pityosporites antarcticus (Seward, 1914), gymnospermous wood (Seward, 1914; Schopf, 1962), possible anthrophyte stems (Schopf, 1962), carbonaceous markings (Arber, 1907; Seward, 1914), fusinized axes (Seward, 1914; Schopf, 1962), and unidentified and tentatively identified microfossils (Schopf, 1962). Records of Antarctic Permian plants not yet substantiated by published descriptions or illustrations are: "araucarian conifer needles" and ,Glossopteris (Barghoorn, 1961) from an unnamed Coal Measures Section in the Queen Maud Mountains, and Lueckisporites amplus, L. limpidus, L. fusus, L. cancellatus, L. spp., Florinites ovatus, Granulatisporites spp., Apiculatisporites spp. and Pityosporites sp. from the Amery Formation (Crohn, 1959). The Glossopteris flora is also reported in the Theron Mountains and Whichaway Nunataks (Stephenson, 1960). Dadoxylon from South Georgia (Gordon, 1930) may perhaps be included, but its age is not clearly established. Fucoids from the Beacon Sandstone in Victoria Land (Zeller, Angino, and Turner, 1961) are reported, but neither their age nor vegetable nature is established. Low-grade Permian coal of high rank (i.e., coal with a high percentage of I Received for publication August 1, 1962. 2 Present address: Dept. of Botany, Washington State University, Pullman, Washington. Contribution No. 16 of the Institute of Polar Studies, The Ohio State University, Columbus, Ohio. This research was supported by grant G-13590 from the National Science Foundation. It has been my pleasure to benefit from the criticisms and advice of Dr. J. M. Schopf, U.S. Geological Survey, and Mr. G. Doumani and Mr. W. E. Long, Institute of Polar Studies, in preparing this paper. mineral matter and a low percentage of volatile matter) is known from several localities (Schopf, 1962). Plants from the Mount Glossopteris Formation (Schopf, 1962) were collected on Mount Glossopteris in the Ohio Range of the Horlick Mountains by an expedition from the Ohio State University's Institute of Polar Studies in December, 1958 (Long, 1959). Subsequently, during the 1960-61 Antarctic field season, W. E. Long and G. Doumani made more extensive collections of plant fossils at 3 localities-Terrace Ridge, an unnamed ridge to the northeast of Terrace lRidge, and Moraine Ridge (Fig. 2 in Long, 1962) on Mount Schopf in the same mountain range. Excluding petrified specimens and disseminated microfossils which need a more protracted study, the plants collected on that expedition form the basis of this report. Most plants from Mount Schopf are preserved in an extremely hard, gray, silty shale which weathers to a light-tan color; a few occur in hard coaly shale. The hardness of the rocks, like the high rank of the coal in the Mount Glossopteris Formation, results from baking by the heat of igneous intrusion and perhaps from over-burden pressure. Consequently, the fossils are preserved as high-rank compressions, but many collected from exposed rock ledges are weathered, and only impressions are left. The structure of the compressions has changed, and even where surface layers can be removed by dissolving the rock in hydrofluoric acid, no outlines of epidermal cells show. No cellular details appear in cellulose acetate peels from leaf surfaces or in leaves studied as transfers. Many specimens were transferred by Ashby's method (Lang, 1926), substituting E-POX-E. glue (Woodhill Chemical Co., 1390 East 34th St., Dept. EPX-1, Cleveland 14, Ohio) for celloidin solution. This method was most useful in studying scale leaves and groups of sporangia. Bulk macerations in hydrofluoric acid mainly provided fragments of fusain and metamorphosed leaves, but some sporangia and seeds were picked out.