A—Unionella carnei, Eth. fil. Triassic. New South Wales
B—Mytilus problematicus, Zittel. Triassic. New Zealand
C—Monotis salinaria, Zittel. Triassic. New Zealand
D—Trigonia moorei, Lycett. Jurassic. W. Australia
E—Astarte cliftoni, Moore. Jurassic. W. Australia
The Queensland Trias (Burrum Formation) contains a solitary species of bivalved mollusca, Corbicula burrumensis. This genus is generally found associated with freshwater or brackish conditions.
In New Zealand marine Triassic beds occur, containing, amongst other genera, a species of Leda. In the succeeding Wairoa Series the interesting fossil, Daonella lommeli occurs. This shell is typical of the Norian (Upper Trias) of the Southern Tyrol. Above the Daonella bed occurs the Trigonia bed, with that genus and Edmondia. In the next younger stage, the Otapiri Series, near Nelson, there are fine-grained sandstones packed full of the remains of Mytilus problematicus ([Fig. 93 B]) and Monotis salinaria ([Fig. 93 C]), the latter also a Norian fossil.
Jurassic Bivalves.—
Jurassic bivalved molluscs are plentiful in the W. Australian limestones, as at Greenough River. Amongst others may be mentioned Cucullaea semistriata, Ostrea, Gryphaea, Trigonia moorei ([Fig. 93 D]), Pecten cinctus, Ctenostreon pectiniforme and Astarte cliftoni ([Fig. 93 E]). Several of the species found are identical with European Jurassic fossils.
Jurassic strata in Victoria, being of a freshwater and lacustrine nature, yield only species of Unio, as U. dacombei, and U. stirlingi.
The Jurassic beds of S. Australia contain a species of Unio named U. eyrensis. In the same strata which contains this shell, plant remains are found, as Cladophlebis and Thinnfeldia, two well-known types of Jurassic ferns.
Lower Cretaceous Bivalves.—