Upper Paleozoic to Triassic marble and intercalated quartzite are exposed on the south tip of Hanmer Island. The marble is highly contorted and quartzite, which may be meta-cherts, is laminated and frequently boudinaged.

The band of pinkish, medium-grained calcium limestone forms a cliff 30 metres high. The limestone is bounded by schist and intruded by diorite dykes.

A sample analysed 91.14 per cent CaCO3, 1.07 per cent MgCO3, 6.12 per cent SiO2, 0.49 per cent Fe2O3, 0.51 per cent Al2O3 and 0.04 per cent Ca3(PO4)2 (Canmet Report 811).