Koonwarra fish-bed (Cretaceous of Australia)

Where: Victoria, Australia (38.6° S, 146.0° E: paleocoordinates 79.0° S, 108.1° E)

• coordinate stated in text

• outcrop-level geographic resolution

When: Korumburra Group, Early/Lower Cretaceous (145.0 - 100.5 Ma)

• The fish-bed occurs within a 7.1 m true thickness of mudstone and represents a still-water environment in the predominantly fluviatile sediments of the Lower Cretaceous Korumburra Group.

• bed-level stratigraphic resolution

Environment/lithology: fluvial; lithified, graded mudstone and lithified claystone

• The Koonwarra fish-bed represents a still-water environment within mainly fluviatile sediments.
• The fish-bed occurs within a 7.1 m true thickness of mudstone and represents a still-water environment in the predominantly fluviatile sediments of the Lower Cretaceous Korumburra Group. It is made up of graded laminae with a composed of alternate layers of siltstone and claystone, The mudstones are contained within a succession of fluviatile arkoses.

Size class: macrofossils

Collected in 1965-1966

Collection methods: bulk

• When the present study commenced in 1965, a small excavation had been made on the northern side of the road, in the area from which most of the fossils had been obtained. This region is limited in extent, being bounded along the strike by the highway and a railway cutting. Permission was therefore obtained from the Country Roads Board to excavate on the western side of the road, above the road-cutting. This was carried out in early 1966 by bulldozing, overburden being removed from an area of about 600 m squared. The fish-bed horizon was then relocated and removal of rock commenced, following the strike and excavating down to a level of 5-6 feet. THe depth of the trench was governed by the dip of the bed (37 degrees) into the spur through which the road-cutting had been driven. About 14-16m cubed of fossil-bearing rock was removed from this south-western exposure. The distance between northern and southern sites is approximately 18.6 m. A trench was subsequently dug at 90 degrees to the strike to enable the beds to be mapped stratigraphically. A further, smaller trench was driven along the strike in the lower region of the fish-bed.

•Specimens repositories: MUZ: Monash University, and MUGD: University of Melbourne, Department of Geology and Mineralogy

Primary reference: M. Waldman. 1971. Fish from the freshwater Lower Cretaceous of Victoria, Australia with comments of the palaeo-environment. Special Papers in Palaeontology 9:1-124 [M. Bell/M. Bell]more details

Purpose of describing collection: taxonomic analysis

PaleoDB collection 140631: authorized by Mark Bell, entered by Mark Bell on 13.03.2013

Creative Commons license: CC BY (attribution)

Taxonomic list

Actinopteri
 Palaeonisciformes - Coccolepidae
? Coccolepis sp. Agassiz 1843
MUZ 314A-D
Coccolepis woodwardi n. sp. Waldman 1971
MUZ 3167AB (type)
 Leptolepidiformes - Leptolepididae
Leptolepis koonwarri n. sp. Waldman 1971
MUGD 3649
 Pachycormiformes -
Koonwarria manifrons n. gen. n. sp., Wadeichthys oxyops n. gen. n. sp.
Koonwarria manifrons n. gen. n. sp. Waldman 1971
MUZ 2797A
Wadeichthys oxyops n. gen. n. sp. Waldman 1971
MUZ 3075AB
Osteichthyes
 Dipnoi - Ceratodontidae
Ceratodus sp. Agassiz 1838 lungfish
MUZ 3343