Field Sites

The Canowindra Story - The Australian Museum and The Age of Fishes

• First discovery, 1956
• Trying to find the site again
• Excavation, 1993
• Preparation by volunteers
• The Canowindra fauna
• More to be found
• Canowindra slide show

First discovery, 1956

In 1956 near Canowindra, central-west New South Wales (300 km west of Sydney), a very rich Late Devonian fish fauna was accidentally discovered during road works. A large rock slab covered with strange impressions was unearthed and moved to the side of the road. A local beekeeper, William Simpson, identified the impressions as fossils, realised their importance and notified Harold Fletcher, the Australian Museum's palaeontologist. The slab was saved, removed to Sydney and placed on permanent public display in the Australian Museum.

The 1956 block contained approximately 114 fish fossils. Strange, long-extinct armoured fishes (placoderms) dominated the fauna: Bothriolepis yeungae Johanson, 1998 and Remigolepis walkeri Johanson, 1997. Also present on the 1956 slab was a single specimen of a new sarcopterygian (lobe-finned) fish, Canowindra grossi Thomson, 1973.

Trying to find the site again

In 1980, while cleaning and re-examining the Canowindra slab, Dr Alex Ritchie, Fletcher's successor as palaeontologist, discovered two small specimens of Groenlandaspis, a Late Devonian placoderm . This was a fish he had earlier discovered, and reconstructed, from Devonian rocks in Antarctica. Following this unexpected discovery, Ritchie visited Canowindra several times between 1973 and 1990 trying, unsuccessfully, to relocate the original site.

Excavation, 1993

In 1993, with the aid of a 22 tonne excavator provided by the local Cabonne Shire Council, Alex Ritchie first relocated and later excavated the Canowindra fossil site. It proved to be a spectacularly rich, unique, world-class fossil assemblage. Some 60-70 tonnes of rock slabs were recovered, covered with impressions of more than 3,700 fish specimens, most of them complete.

Preparation by volunteers

Preparing such an enormous quantity of fossil specimens for study presented a major problem. From 1993 to 1999 monthly groups of paying volunteers, organised by Gondwana Dreaming, a local eco-tourism organisation, helped Australian Museum scientists to clean and cast the fossils. These were studied and described by Dr Zerina Johanson, Australian Museum, in association with Dr Per Ahlberg, Natural History Museum, London.

The Canowindra fauna

The Canowindra fauna is now known to include eight taxa, the four found on the 1956 slab plus others new to science. All of the fossil specimens are preserved on a single bedding plane, part of an ancient fish community which had been trapped in a pool of water which dried up, killing the fish. Incoming sediments later buried these fishes quickly and quietly, with minor disturbance to the fish skeletons.

The fauna is dominated by two species of antiarch placoderms (armoured fishes), Bothriolepis and Remigolepis (97% of the fauna). Groenlandaspis, an arthrodiran placoderm, is much rarer, with only about 50 specimens recovered. The sarcopterygians (lobe-finned fishes) are even rarer, with the remains of approximately 20 individuals so far noted. Along with Canowindra grossi, the sarcopterygian taxa Mandageria fairfaxi Johanson & Ahlberg, 1997, Cabonnichthys burnsi Ahlberg & Johanson, 1997, Gooloogongia loomesi Johanson & Ahlberg, 1998 and Soederberghia simpsoni Ahlberg et al., 2001 have been described. Soederberghia simpsoni is a lungfish, a group with a good fossil record, but today known only from three genera in South America, Africa and Australia (the Queensland lungfish, Neoceratodus). Soederberghia is also known from a Late Devonian locality near Forbes, New South Wales, and from Pennsylvania, U.S.A. and East Greenland.

The 200 fish-covered slabs recovered in 1993 are stored at Canowindra, and a selection of the most important slabs and fossil specimens are on display at Canowindra's new Age of Fishes Museum.

More to be found

Although most of the Canowindra fauna has now been described, much more still lies underground at the original site on Gooloogong Road - temporarily reburied in 1993 to protect this unique fossil layer from vandalism. Almost certainly many thousands of fish specimens remain buried at Canowindra, and they probably include other taxa new to science.

The Canowindra site has now been listed as part of Australia's National Heritage because of its international scientific importance. Further investigation will depend on adequate funding becoming available to reopen the site, to uncover the fish layer, and to continue excavating it under controlled conditions. Only then will we gain a better understanding of the palaeoecology of the Canowindra fauna and the processes involved in their burial and preservation as fossils.

Ideally such studies would take place under cover in a specially constructed building, and in the process providing a unique tourist attraction. Visitors would be able to view these ancient fishes lying just where they died around 360 million years ago, and watch scientists at work excavating, casting and studying them.

Copyright © Australian Museum 2002