New Devonian plant fossil occurrences on the New South Wales South Coast: geological implications

Abstract

Devonian fossil localities are summarised for coastal southeastern Australia, including both marine invertebrates representing a major late Frasnian (Late Devonian) transgression, and plant remains of Middle–Late Devonian age in associated non-marine strata. Lycopsid plant specimens (Leptophloeum) from near Majors Creek, NSW, first documented by Edgeworth David and E. F. Pittman in association with marine fossils to demonstrate a Late Devonian age, are illustrated for the first time. Lycopsid plants of presumed Middle Devonian age are illustrated from three new localities: Yowrie River inland from Cape Dromedary, Tuross River northwest of Narooma and Charlies Forest Road northeast of Braidwood. The Yowrie River occurrence (in float) indicates probable Middle Devonian strata upstream that are not shown on published maps. The Tuross River occurrence is in sheared and folded strata previously mapped as Ordovician, and the Braidwood occurrence demonstrates Devonian black shales adjacent to previously mapped Ordovician. Evidence supporting alternative thrust or simple fold interpretations for the Budawang Synclinorium is discussed, and relevant Ordovician fossil localities are listed.

Keywords:

• Devonian
• lycopsid plants
• Leptophloeum
• Lepidosigillaria
• stratigraphy
• correlation
• Budawang Synclinorium
• Ordovician unconformity

Acknowledgements

We thank C. Rumble for details about the Yowrie River fossil discovery, and collector W. Smith for providing the specimen for study and donating it to the Australian Museum. E. Papp conducted a geophysical survey for the Bodalla groundwater project and introduced the Devonian field geology of the Nerrigundah Road locality. B. Meyer-Berthaud (Montpellier), and J. Pickett (Sydney) provided advice on Devonian plants and invertebrates, respectively. E. Papp, P. Ollerenshaw, T. Senden and B. Young assisted during field work. Information on Devonian plant collections in Museum Victoria and the Australian Museum was provided by D. Holloway and G. McLean respectively. R. Jones (Australian Museum) gave information on Devonian invertebrate localities in Morton National Park. Field examination in Mimosa Rocks and Ben Boyd National Parks was covered by collecting permits from NSW National Parks & Wildlife Service, and S. Dovey, C. Dickman, S. Deck, B. Evans, H. Hayward and N. Ross are thanked for assistance. J. W. Pickett and A. J. Wright are thanked for helpful reviews of the manuscript. This paper is dedicated to the memory of noted paleobotanist Dr Mary White, who died (August 5, 2018) during the final revision of this manuscript.

Additional information

Funding

The research was supported by ARC Discovery Grants DP0558499 and DP0772138. Provision of facilities in the Department of Applied Mathematics, ANU is gratefully acknowledged.