Plant Fossils from the Ellsworth Mountains
of different lithology. In the absence of diagnostic paleontologic References evidence, this proposal can only be postulated. Finally, the Cretaceous/Tertiary contact may occur at some other, as yet undefined, horizon between the highest ammonite level in the uppermost Lopez de Bertodano Formation and the level of the first Paleocene silicoflagellates in the lowermost Askin, R.A. 1984. Palynological investigations of the James Ross Island Sobral Formation. This is based on the assumption that am- basin and Robertson Island, Antarctic Peninsula. Antarctic Journal of monites were restricted to the Cretaceous. The possibility that the U.S., 19(5), 6 - 7. ammonites may have survived into the Tertiary should not be Harwood, D.M. 1985. Personal communication. ignored, however. Huber, B.T., D.M. Harwood, and P.N. Webb. 1983. Upper Cretaceous microfossil biostratigraphy of Seymour Island, Antarctic Peninsula. Because of the absence of Tertiary indicator species between Antarctic Journal of the U.S., 18(5), 72 - 74. the glauconite bed of the upper Lopez de Bertodano Formation Huber, B.T., D.M. Harwood, and P.N. Webb. 1985. Distribution of micro- and the lower Sobral Formation, a zone of uncertainty, repre- fossils and diagenetic features associated with the Cretaceous - Tertiary senting 73 meters of section, is shown for the location of the boundary on Seymour Island, Antarctic Peninsula. (Unpublished ab- Cretaceous/Tertiary contact on Seymour Island (figure 1). It is stract.) Conference on Rare Events, International Geological Correla- hoped that examination of sample material collected during the tion Programme, Project 199, GWATT, Switzerland, May 20 - 22. 1985 field season will reveal age-diagnostic microfossils in this Macellari, CE., and W.J.
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