Unionoid

II. n. Same as unionid.

Carbonicola, of the Devonian and Carboniferous, comprises Unionoid Bivalves, with thick shells, an external ligament, and a concentrically-striated surface.

I know nothing of that of Solenaia beyond the statement of Fischer regarding its greatly developed, mushroom shaped foot and its burrowing habit. It is, I am satisfied, an unionoid animal and the fact that there is a decided posterior pallial sinus to the shell leads me to believe that it has two siphons.

The current record of Australian Lower Cretaceous non-marine macroinvertebrates is substantial but mainly limited to a few highly productive localities. Some remains have been recovered from near-shore marine rocks including the Valanginian Trinity Well Sandstone Member of the Cadna-owie Formation (South Australia) and the Aptian Wallumbilla Formation (White Cliffs, New South Wales). These have produced freshwater unionoid bivalves (Alathyria coatsi, Hyridella whitecliffsensis) and Australia’s oldest known non-marine gastropod – the viviparid Notopala alboscopularis.