The landscape of Lamington National Park is basically the result of two large, ancient volcanoes.

(Diagram coming soon)

Before the volcanic activity, the rock type was sedimentary rock, which was deposited when the area was under sea level. This sedimentary rock built up to form older hills and valleys.

The two volcanoes, Focal Peak Volcano and Tweed Shield Volcano, erupted, spewing lava over the hills and valley, dramatically changing the landscape into the mountainous areas that it is today. Some scientist believed this to occur around 24 million years ago.

Focal Peak Volcano was situated to the west, near the present Mount Barney. The early eruptions were comprised of basalt, a very dark rock containing many minerals. Due to the fluid nature of basalt, the low valleys towards Beudesert and Kyogle and later as far as Beechmont in the east where first covered. 

Later the lava flows changed composition to rhyolite, being less fluid than basalt was more restricted in its flow. This rock is responsible for the Mount Gillies Volcanics. At the end of the volcanic activity of Focal Peak
Volcano, a large mass of rhyolite solidified beneath the volcano. As this rock cooled, it formed granophyre, a rock with larger crystals (but not as large as granite). Pressure from below thrust this granophyre mass upwards, creating circular fractures from which more rhyolite squeezed through. Erosion of this mountain (now Mount Barney) then caused a thin layer of gravel to be spread over its flanks, the Chinghee Conglomerate.

Larger and erupted shortly after the Focal Peak Volcano, the Tweed Shield Volcano was centred over the present Mount Warning (New South Wales). The central summit of this volcano is estimated to have been around 2000 m above sea level. 

The lava flows covered much of the lavas from the Focal Peak Volcano in the west as well as many of the older rocks in the east. This volcano built up a broad, gently sloping dome (a shield) of many basalt lavas. These extended over the present border ranges, as far as at least Tamborine Mountain in the north, Lismore in the south and Mount Lindesay in the west. 

Unlike basalt eruptions, which are relatively quiet with the highly fluid lava flowing long distances from the vents, is the activity that formed the Binna Burra Rhyolite. The early eruptions that formed this rhyolite were highly gas charged and explosive. This resulted in the release of fragments and beds of tuff and agglomerate accumulated.

Erosion of the resulting rock from the volcanoes then occured which resulted in the landscape of Lamington National Park.