The Malbina siltstone and sandstone

The Malbina Siltstone and Sandstone overlies the Cascades Group and underlies the Risdon Sandstone in the Hobart area, Tasmania. This unit has been called" Woodbridge Glacial Formation" and other names. In the type section five members can be recognized:-" A", a basal sandstone; followed by "B", a siltstone; "C", a thin pebbly sandstone; "D ", a siltstone; and" E ", the uppermost richly fossiliferous sandstone and siltstone. Some of the sandstone beds are poorly sorted and graded. The silts were deposited in deep water and deposition of silt was inter-- from time to time by inrushes of turbidity currents bringing pebbles, sand and shells from shallower water. Erratics indicate the presence of rare icebergs. The formation is Upper Artinskian or Kungurian.