|List||National Heritage List|
|Legal Status||Listed place (11/01/2007)|
|Place File No||2/07/107/0002|
|Summary Statement of Significance|
Yea Baragwanathia Flora Fossil
Site has deposits containing pioneer vascular land-plant floras and ancient
invertebrates of international significance. It is the oldest known Baragwanathia
flora fossil site in the world, providing significant information about the
evolution of early land plants. This site, with its Lower Plant Assemblage,
includes many more members of the Baragwanathia flora and has a richer associated marine
fauna than any other site, and importantly, the specimens are better preserved.
Specimens of the primitive club moss, Baragwanathia
longifolia, and other Baragwanathia flora occur as
part of an extensive floral assemblage in graptolite-bearing beds dating to the
Late Silurian age (about 415 million years ago). Barclays Cutting is one of
only two Baragwanathia
localities with graptolites (jellyfish-like colonial marine invertebrates) and
an extensive floral fossil assemblage in close association, and is the site
with the best and richest such fossils in Australia.
These plant fossils considerably predate club mosses (lycopods) found in the Northern Hemisphere fossil record. They provide evidence of the extensive evolution and development of early vascular plants, and most significantly, adaptations of plants from the sea to the land. Fossil evidence from the Yea site indicates that land plants may have developed first in the Southern Hemisphere.
The Yea Baragwanathia fossil site is the best example exposing the older Lower Plant Assemblage in Australia. It contains representatives of the Baragwanathia flora, including Baragwanathia longifolia and an unusually high number of other early vascular land plants such as Drepanophycus sp., Yarravia sp., Hedeia sp. and Salopella australis sp. nov.
The site has strong associations with the internationally renowned pioneer palaeobiologist Dr Isabel Cookson (1893-1973) who described the Yea Baragwanathia fossils in 1935. Cookson, a Research Fellow in Botany, University of Melbourne (1952-1959) was world renowned for her research on fossil plants. She created many international collaborations and associations that led to significant discoveries. The Cooksonia plant genus (containing the oldest known land plants) and the Isabel Cookson Award (Botanical Society of America) have been named in her honour.
The Yea Baragwanathia Flora Fossil site (Barclays Cutting) is the
locality of the oldest known vascular land plants in Australia, and one of the oldest
known localities for such a fossil assemblage in the world. Australia was
very different during the Silurian and much closer to the equator. A large sea
occupied central Victoria and there were volcanoes on the New South Wales /
Victorian border. Most significantly, the remarkable evolution of vascular
plants occurred during this time, with adaptations of lower plants from the sea
to the land. The Baragwanathia
flora assemblage contains the earliest vascular land plants, including a key
member, Baragwanathia longifolia,
after which the assemblage is named. B. longifolia
was a primitive club moss (lycopod) with a stout stem covered with spirally
arranged, long, simple needle-like leaves and reaching up to one metre in
height. It is amongst the oldest land plants yet recognised in the world.
Another species of Baragwanathia
has been described from Ontario in Canada
but in rocks of late Devonian age, at least 25 milion
years younger than the Yea specimens. Other simple plants that occur as part of
flora assemblage include species of the lycopsid Yarravia, the rhyniophyte Hedeia
and various algae. These plants most probably occupied moist habitats such as
coastal environments and river flats and were large enough to modify the
landscape with thicket-forming vegetation. |
Because the fossil site is comprised of marine sediments, it is theorised that an event such as a flood washed some of these plants into the sea, where they were preserved in shallow marine sediments. The group of plant fossils associated with the site is known from a range of other younger fossil sites in eastern Australia dating to the early Devonian. The Barclays Cutting site is the only site that can be definitively dated to the Silurian period (10 to 20 million years earlier) because of the presence of particular extinct marine invertebrate fossils known as graptolites. Graptolites were small, stick-like, colonial marine animals now long extinct which were widespread through the seas of the Palaeozoic.
Located in and immediately adjoining a road cutting on a barren hillside, the Yea Baragwanathia Flora Fossil Site occurs within an area of anticlines and synclines with clearly defined fold belts. An anticlinal belt passes through Yea township, exposing the oldest sediments of the area within its core. A number of distinct, ancient fauna and flora fossil assemblages occur in the Yea area, all of which include elements of the Baragwanathia flora. The more recent, Early Devonian (Praguian) assemblage is referred to as the Upper Plant Assemblage and the older Late Silurian (Ludlovian) assemblage is referred to as the Lower Plant Assemblage. They are separated stratigraphically by 1700m of unfossiliferous strata characterised by dark, grey green, siltstones. Steeply dipping Silurian sediments contain the oldest members of the Baragwanathia flora assemblage of the Late Silurian. This occurs in thin brown to grey claystones of the Yea Formation, beneath the Rice's Hill Sandstone Member comprising a 70m thick sequence of grits and interbedded sandstones and siltstones. Two principal plant bands are exhibited in a well-laminated, buff-grey, fine-grained sandstone which splits easily along laminae (each about 30 cm in width). A more restricted buff-orange band of slightly coarser sandstone forms the upper band, with a prominent marker bed containing marine fossils, principally orthoceratids (octopus-like nautiloids) and large pelecypods (benthic aquatic molluscs). Marine fauna identified include the pteropod Hyolithes, bivalve Necklania, brachiopod Maoristrophia banksi, and at a few sites, the graptolites Bohemograptus bohemicus, Pristiograptus dubius, Monograptus aff. uncinatus and Saetograptus. The lower plant band consists of beds containing small oval-round algae 1-4 cm in diameter and a prominent quartz vein 10 cm thick overlain by an indurated red-brown band 5-10 cm thick occasionally bearing plant remains. The beds separating the plant bands are less well laminated and contain a prominent siltstone band 10 cm thick that forms an uneven surface on splitting.
Baragwanathia fossils were first discovered at Yea in 1875 and subsequently jointly described by Australia’s eminent pioneer palaeobiologist Dr Isabel Cookson and Professor William Lang from Manchester University in 1935. Cookson (1893-1973) lectured in Botany at the University of Melbourne 1930-1951 and was a Research Fellow from 1959. Cookson developed a keen interest in fossil plants during the first of many research trips to the University of Manchester in 1926. She created many international collaborations and associations that led to significant discoveries. World-renowned for her research on fossil plants spanning a career of 58 years, Cookson published over 80 papers, produced many botanical illustrations and was recognised as a Doctor of Science. The Cooksonia plant genus (containing the oldest known land plants) was named in her honour and the Botanical Society of America commemorate her with an annual award for the best paper on palaeobotany. The Isabel C Cookson Research Laboratory for Palaeobotany and Plant Morphology at the School of Botany, Melbourne University, is named after her.
The name Baragwanathia was given to these particular plant fossils in recognition of the collection of the first specimens by Mr William Baragwanath (1878-1966), a geologist who was Director of Geological Survey in Victoria from 1922 to 1924 and Chief Mining Surveyor from 1924 to 1932.
Baragwanathia noted nearby, 1941.|
Fragmentary Baragwanathia noted, 1960s and 70s.
Council widens cutting, exposing richest Baragwanathia bed known, 1979.
Council demolishes portion of bed above road level, 1979.
Council excavates below road level for international conference to provide new access to fossil beds, 1982.
|Condition and Integrity|
Barclays Cutting was subject to disturbance from quarrying
and road construction in 1979, but the Local Council has been actively managing
the fossil site since then. Although the surface material was damaged, the huge
pile of resultant rubble yielded many fine specimens of Baragwanathia and other fossils.
Access to further in situ fossils would require bulldozing of subsurface
material (Douglas and Holmes 2006).|
1.5km east-south-east of Yea, comprising the area within a circle of radius 200m
centred on AMG point: 7923 Yea 362300mE 5879330mN
(MGA point 362420mE 5879480mN).|
Australian Science and Technology Heritage
Centre 2005. Bright Sparcs
biography entry for Isabel Cookson. At http://www.asap.unimelb.edu.au/bsparcs/bsparcshome.htm,
accessed 31 October 2005.|
Birch, W.D. (editor) 2003. Geology of Victoria, 3rd edition. Special publication 23, Geological Society of Australia, 842 pp.
Chapman, F. 1914. On the palaeontology of the Silurian of Victoria. Rep. Aust. N.Z. Assoc. Adv. Sci., 14th Meeting; 207-235.
Cookson, I.C. 1935. On plant remains from the Silurian of Victoria, Australia, that extend and connect floras hitherto described. Phil. Trans. Roy. Soc. Lond. 225;127-148.
Cookson, I.C. 1949. Yeringian (Lower Devonian) plant remains from Lilydale, Victoria, with notes on a collection from a new locality in the Siluro-Devonian sequence. Mem. Nat. Mus. Vic. 16;117-131.
Couper, J. 1965. Late Silurian to Early Devonian stratigraphy of the Yea-Molesworth district, Victoria. Proc. R. Soc. Vict., 79; 1-9.
Douglas, J.G. 1976. Some additions to the Baragwanathia flora. Unpub. Rep. Geol. Surv. Vict., 1976/81.
Douglas, J.G. 1976. Baragwanathia flora from Yea. Unpub. Rept. 1976/81 Mines Dept. Vic.
Douglas, J.G. & Ferguson, J.A. (eds) 1988. Geology of Victoria. Geological Society of Australia, Victoria Division, Melbourne.
Douglas, J. & Holmes, F. (2006). The Baragwanathia story: an update. The Fossil Collector, 77, 9-26, January 2006.
Garratt, M.J. 1976. On the probable Silurian Age for the earliest Baragwanathia flora. Unpubl. Rept. 1976/80 Mines Dept.
Garratt, M.J. 1976. Evidence for Silurian (Ludlovian) age of the earliest Baragwanathia flora. Abst. 2nd Geol. Conv. Geol. Soc. Aust., Monash, 14.
Garratt, M.J. 1977. New evidence for Silurian Age for earliest Baragwanathia flora. Abst. 2nd Geol. Conv. Geol. Soc. Aust., Monash Feb. 1977.
Garratt, M.J. 1978. New evidence for a Silurian (Ludlow) age for the earliest Baragwanathia flora. Alcheringa 2;217-224.
Garratt, M.J. 1981. The earliest vascular land plants: comment on the age of the oldest Baragwanathia flora, Lethaia, 14;8. Oslo.
Garratt, M.J. & Rickards, R.B. 1984. Graptolite biostratigraphy of early land plants from Victoria. Proceedings of the Yorkshire Geological Society, V.44;377-384.
Garratt, M.J., Tims,J.D., Rickards, R.B., Chambers, T.C. & Douglas, J.G. 1984. The appearance of Baragwanathia (Lycophytina) in the Silurian. Botanical Journal of the Linnean Society 80;355-8.
Garratt, M.J. & Rickards, R.B. 1987. Prodoli (Silurian) graptolites in association with Baragwanathia (Lycophytina). Bulletin Geological Society Denmark, V.35;135-139. Copenhagen.
Harris, W.J. & Thomas, D.E. 1942. Notes on the Silurian rocks of the Yea district. Min. Geol. J. Vict. 2; 302-304.
Jaeger, H. 1966. Two late Monograptus species from Victoria, Australia and their significance for dating the Baragwanathia flora. Proc. R. Soc. Vict. 79;393-413.
Jaeger, H. 1970. Remarks on the stratigraphy and morphology of Pragian and probably younger monograptids, Lethaia, 3;173-182.
Joyce, E.B. and R. L. King (eds) 1980. Geological features of the National Estate in Victoria. Geological Society of Australia Inc. Victorian Division, Melbourne.
Lang, W.H. & Cookson, I.C., 1927. On some early Palaeozoic plants from Victoria, Australia. Mem. Proc. Manch. Lit. Phil. Soc. 71;41-51.
Lang, W.H. & Cookson, I.C. 1935. On a flora, including vascular land plants, associated with Monograptus in rocks of Silurian age, from Victoria, Australia. Phil. Trans. Roy. Soc. Lond. 224;421-449.
Lang, W.H. 1930. Some fossil plants of Early Devonian type from the Walhalla Series, Victoria, Australia. Phil. Trans. Roy. Soc. Lond. 219;133-161.
Mitchell, M. M., Cochrane R.M. & King R.L. 2000. Sites of geological significance in the Melbourne 1:250 000 mapsheet area. Geological survey of Victoria Technical Record 2000/1.
Rickards, R.B. 2000. The age of the earliest club mosses: the Silurian Baragwanathia flora in Victoria, Australia. Geol. Mag. 137(2);207-209. Cambridge University Press.
Rickards, R.B. & Garratt, M.J. 1990. Pridoli graptolites from the Humevale Formation at Ghin Ghin and Cheviot, Victoria, Australia. Proceedings of the Yorkshire Geological society 48;41-6.
Rickards, R.B. & Sandford, A.C. 1998. Llandovery-Ludlow graptolites from central Victoria: new correlation perspectives of the major formations. Australian Journal of Earth Sciences 45;743-63.
Rickards, R.B. & Wright, A.J. 1999. Evolution of the Ludlow (Silurian) graptolite genus BOHEMOGRAPTUS Pribyl 1967. Proceedings of the Yorkshire Geological Society 52;313-20.
Tims, I.D. & Chambers, T.C. 1984. Rhyniophytina and Trimerophytina from the early land flora of Victoria, Australia. Palaeontology 27;265-279.
Vandenberg, A.H.M., Garratt, M.J. and Spencer-Jones, D. 1976. Silurian-Middle Devonian. In J.G. Douglas & J.A. Ferguson (eds) Geology of Victoria. Geological Society of Australia Special Publication 5;45-76.
White, M.E. 1988. Australia’s Fossil Plants. Reed Books Pty Ltd, Frenchs Forest NSW, 144 pp.
White, M.E. 1990. The Baragwanathia flora of Victoria. pp 67-71 in: The Greening of Gondwana - the 400 million year story of Australia's plants. Reed Books Pty Ltd, Frenchs Forest NSW, 256 pp.
Yeates, A.N. 2001. An assessment of Australian geological sites of possible national or international significance, Volume 2: Fossils, pp 136-138. Report prepared for the Australian Heritage Commission, 182 pp.
Report Produced Mon Dec 9 14:51:58 2013