Australia

In eastern Australia, Paleozoic era volcanic activity built up much of the rock strata. Mountain glaciation during the late Carboniferous period when insects, amphibians, and early reptiles first evolved, also transformed the landscape. Mountain building in eastern Australia culminated during the middle and later Permian period (about 250 million years ago) when a huge mass of magma (underground molten rock) was emplaced in older rocks in the New England area of northeastern New South Wales. This huge mass or batholith, caused extensive folding to the west and ended the sedimentation phase of the Tasman geosyncline. It was also the last major episode of orogeny (mountain building) on the continent.