A—Aff. Carposphaera (after David and Howchin). Cambrian. Brighton, S.A.
B—Cenosphaera affinis, Hinde. Mid. Devonian. Tamworth, N.S.W.
C—Amphibrachium truncatum, Hinde. Up. Cretaceous. Pt. Darwin.
D—Dictyomitra triangularis, Hinde. Up. Cretaceous. Pt. Darwin.
The large number of fifty-three species have been found in the radiolarian rocks of Middle Devonian age at Tamworth in New South Wales ([Fig. 66]). These have been referred to twenty-nine genera comprising amongst others, Cenosphaera, Xiphosphaera, Staurolonche, Heliosphaera, Acanthosphaera and Spongodiscus.
Cretaceous Radiolaria.—
Although certain silicified rocks in the Jurassic in Europe have furnished a large series of Radiolaria, the Australian marine limestones of this age have not yielded any of their remains up to the present. They have been found, however, in the Lower Cretaceous of Queensland, and in the (?)Upper Cretaceous of Port Darwin, N. Australia. The Radiolaria from the latter locality belong to the sub-orders Prunoidea, Discoidea and Cyrtoidea ([Fig. 66]). The rock which contains these minute fossils is stated to be eaten by the natives for medicinal purposes. As its composition is almost pure silica, its efficacy in such cases must be more imaginary than real.
Cainozoic Radiolaria.—
Cainozoic rocks of Pliocene age, composed entirely of Radiolaria, occur at Barbados in the West Indies. No Cainozoic Radiolaria, however, have been found either in Australia or New Zealand up to the present time.