The importance of the geological features was brought to the Heritage Council's attention by Dr. Suzanne Wass of Macquarie University's School of Earth Sciences.

The Kiama Sandstone member forms a narrow wave-cut platform and adjacent vertical cliff face around the south-eastern extremity of the quarry.

The red-brown colour (due to oxidization of haematite) of the sandstone contrasts markedly with the grey-black latite, which displays spectacular columnar jointing elsewhere in the quarry.

[1] Petrographic descriptions of the latite emphasise its conspicuous porphyritic texture; large labradorite to andesine phenocrysts with minor clinopyroxene are set in a groundmass of feldspar microlites with interstitial chlorite and iron oxide.

[1] A capping of cream-coloured weathered latite, still retaining the characteristic porphyritic texture, maybe studied at the top of the northern and western quarry faces.

One of the dykes is geologically unique and contains abundant xenoliths which represent material brought up to the Earth's mantle, about 80 kilometres below the surface of Eastern Australia.

The Bombo Latite Member is also of international scientific significance in providing one of several samples upon which the concept and limits of Kiaman Magnetic Interval were defined.