Ad22, Bird Rock, Torquay (Oligocene of Australia)

Where: Victoria, Australia (38.3° S, 144.3° E: paleocoordinates 52.9° S, 142.2° E)

• coordinate based on nearby landmark

• outcrop-level geographic resolution

When: Jan Juc Formation, Chattian (28.1 - 23.0 Ma)

• STRATIGRAPHIC RELATIONS: McCoy described the locality as from the "Miocene junction beds" or the "passage beds of the Tertiary sands" or just "sandy beds." Both the Jan Juc and overlying Puebla Formations are exposed at Bird Rock, but the Jan Juc Formation is coarser-grained. The associated fauna is also more characteristic of the Jan Juc Formation. AGE: Late Oligocene according to molluscan biostratigraphy of Darragh and Kendrick (2000) and Beu and Darragh (2001). Kelly et al. (2001) reported an age of 23.9 Ma for the basal Puebla Clay from Bird Rock, based on measured 87Sr/86Sr ratios from planktonic foraminifera, recalculated to 23.89-21.39 Ma by McLaren et al., 2009. McLaren calculated an age of 27.2-24.8 Ma for brachiopod shells (87Sr/86Sr) located about 7.5 m below the top of the Jan Juc Formation. Siesser (1979) found a possibly mid-Rupelian to earliest Aquitanian range for the Jan Juc Formation (NP24-NN1) and an early Miocene (NN2-NN4) age for the overlying Puebla Formation. Planktonic foraminifera in Li et al. (1999), including Globoquadrina dehiscens, suggest an early Aquitanian (M1b or mid N4) age for the basal Puebla Formation. Together, these lines of evidence support a latest Chattian age for the collection, although it could be basal Aquitanian. STRATIGRAPHIC POSITION: The description as "junction beds" or "passage beds" suggests that the collection is from the upper part of the formation, close to the distinct lithological contact with the Puebla Formation.

• group of beds-level stratigraphic resolution

Environment/lithology: deep subtidal shelf; poorly lithified, bioturbated, glauconitic, shelly/skeletal, argillaceous wackestone

• ENVIRONMENT: According to Kelly & Webb (1999), their fine-grained, poorly sorted character and the excellent preservation state of many of the fossils indicate deposition in a fairly deep, low-energy regime. Palaeodepth estimates for the Jan Juc and Puebla Formations, based on ostracod and foraminiferal faunas, are mid-shelfal, i.e. probably less than 120 m. According to Li et al., (1999), A lack of foraminifers commonly found from outer shelf and slope suggests that the sequence was mainly deposited in inner to mid-shelf environments. Jan Juc Formation also described as intermediate neritic by Li et al. (1999).
• LITHOLOGY: Uppermost 3 m of the Jan Juc succession at Bird Rock is composed of skeletal packstones, locally glauconitic and bioturbated (Kelly & Webb, 1999). Li et al. (1999) describe a core at Bird Rock as containing interbedded glauconitic marls and clayey glauconitic wackestones, interbedded with thin (bryozoan) skeletal grainstone and mollusc packstone layers. LITHIFICATION: Some units are described as lithified grainstone but the skeletal packstone is "very poorly indurated" (Kelly & Webb, 1999).

Size class: macrofossils

Preservation: original aragonite

Collected by R. Daintree in 1861

• Collections are registered in the Western Australia Museum (WAM) and Museum of Victoria (NMV).

Primary reference: F. McCoy. 1874. Decade I. Prodromus of the Palaeontology of Victoria 1-43 [L. Villier/L. Villier/M. Uhen]more details

Purpose of describing collection: taxonomic analysis

PaleoDB collection 176279: authorized by Pete Wagner, entered by Pete Wagner on 05.02.2016, edited by Matthew Clapham

Creative Commons license: CC BY (attribution)

Taxonomic list

• COVERAGE: Exhaustive for gastropoda and bivalvia. NOMENCLATURE: Includes both antiquated (Tate 1880's) and modern nomenclature, but all at species-level resolution. Nomenclature revised following Darragh (1980 and later texts).
Anthozoa
 Pennatulacea -
Graphularia robinae4 McCoy 1877 sea pen
Bivalvia
 Arcida - Limopsidae
"Limopsis aurita" = Limopsis (Limopsis) aurita2
"Limopsis aurita" = Limopsis (Limopsis) aurita2 Brocchi 1814 clam
 Arcida - Cucullaeidae
Cucullaea corioensis3 McCoy 1876 clam
 Cardiida - Cardiidae
"Cardium pseudomagnum" = Hedecardium (Hedecardium) pseudomagnum4
"Cardium pseudomagnum" = Hedecardium (Hedecardium) pseudomagnum4 McCoy 1877 cockle
 Trigoniida - Trigoniidae
"Trigonia semiundulata" = Eotrigonia semiundulata2
"Trigonia semiundulata" = Eotrigonia semiundulata2 Jenkins 1865 clam
Gastropoda
 Neogastropoda - Volutidae
Voluta anticingulata McCoy 1874 volute
Voluta macroptera McCoy 1874 volute
 Sorbeoconcha - Cypraeidae
Zoila glomerabilis1, "Cypraea (Aricia) platyrhyncha" = Umbilia (Umbilia) platyrhyncha3
Zoila glomerabilis1 Darragh 2011 cowry
"Cypraea (Aricia) platyrhyncha" = Umbilia (Umbilia) platyrhyncha3 McCoy 1876 cowry
Cephalopoda
 Nautilida - Aturiidae
"Aturia australis" = Aturia cubaensis3
"Aturia australis" = Aturia cubaensis3 Lea 1841 nautiloid
Aturia ziczac var. australis
Echinoidea
 Spatangoida - Paleopneustidae
"Pericosmus compressus" = Pericosmus crawfordi5
"Pericosmus compressus" = Pericosmus crawfordi5 Hutton 1873 heart urchin