Late Permian uplift associated with the New England foreland loading phase resulted in the formation of depocentres with the northeast Sydney Basin with best preserved marine fossils. These depocentres filled with pyroclastic and alluvial-paludual sediments of the Newcastle Coal Measures. In the Triassic, uplift of the offshore basin resulted in reworking of Permian sediments in fluvial environments. The basin underwent a final phase of deformation (thrusting) in the Middle Triassic where it was uplifted to become dry land, with an erosion occurring from this time to the present.