Fossils in Talbragar, NSW

Author(s)

Yong Yi Zhen
Updated

10/11/18
Read time

2 minutes

Podozamites jurassica is an extinct conifer plant from the middle to late Jurassic (166-145 million years old) Talbragar Fossil Fish Bed. This fossil site has produced hundreds of beautifully preserved fossils of plants, insects and fish. Podozamites is thought to be closely related to the Wollemi Pine (Wollemia nobilis), a ‘living fossil’ that is now only found within a small rainforest pocket about 150 km north-west of Sydney. This slab shows the perfectly preserved leaves of Podozamites and a fossil fish. Image: Abram Powell
© Australian Museum

Where is Talbragar?

The Talbragar fossil site is located about 30 km northeast of Gulgong, New South Wales, and is registered as Crown Land Reserve for the preservation of fossils. Permission is required for site access, and collection of rock and fossil specimens from this locality is prohibited.

Why is Talbragar important?

Talbragar is one of the most significant Jurassic terrestrial fossil deposits in Australia. It is also the only Jurassic fish site found in New South Wales.

Fossil time period: Talbragar

The shales and siltstones of Talbragar are thought to have been the erosional remnant of sediments from a Jurassic (205 - 141 million years ago) freshwater lake situated at a high latitude within the Gondwanan landmass. Abundant fish lived in the lake surrounded by lush forest. Eventually, their remains accumulated and were buried in the muds at the bottom of the lake, and were beautifully preserved in the finely laminated siltstone as fossils.

Geological setting and stratigraphy

The siltstone or cherty mudstone of the fossil bearing rocks are a part of the Purlawaugh Formation of Jurassic age and occur as loose floating blocks in soil and in situ weathered, indurated (hardened) shales over an area of approximately 300 m by 80 m on the north-eastern side of Farrs Hill. Stratigraphically they are overlain by remnants of Neogene basalt and Jurassic Pilliga Sandstone and underlain by Triassic Narrabeen Sandstone.

Talbragar fossils

Superb preservation

Fossil-bearing slabs are weathered into rectangular blocks exhibiting concentric iron-stained bands. Fossil leaves are typically white in colour making a strong contrast to the surrounding brownish or yellowish rock matrix. With over one hundred years of collecting, the fossil bearing lens has been extensively excavated and almost quarried out. A huge amount of rock has been removed from the site. Beautiful fish and plant specimens are found in the collections of many museums and galleries in Australia and around the world.

Treasures revealed - fauna and flora

Over 25 species are represented from this site including 16 species of plant fossils, eight species of fish fossils, several species of insect fossils, and an undescribed spider, all of which are unique to the locality.

Evolutionary links to modern species

One of the common coniferous plant fossils found at this site is Agathis jurassica. The genus Agathis is extant, representing a small group of some 21 species mainly distributed in Australasia, belonging to the same family (Araucariaceae) as Wollemia. In fact, Agathis jurassica is believed to be closely related to a 'living fossil', the Wollemi pine (Wollemia nobilis). This is a relic coniferous tree species with a small population of less than 100 trees found growing wild in 1994 within a tiny rainforest pocket about 150 km north-west of Sydney.

Key references

White. M.E., 1981a. Fish beds reveal lush fossil forest. Australian Natural History 20 (7), 227-230.
White. M.E., 1981b. Revision of the Talbragar Fish Bed Flora (Jurassic) of New South Wales. Records of the Australian Museum 33 (15), 695-721.
Woodward, A.S., David, T.W.E. and Pittman, E.F., 1895. The fossil fishes of the Talbragar Beds (Jurassic?), with a note on their stratigraphical relations. Memoir Geological Survey of New South Wales, Palaeontology 9, 1-27.