Lithologically it is a grey to dark grey, fine-grained, thinly bedded, argillaceous and often nodular or banded limestone with interbedded calcareous shale, locally bituminous and pyritic. Characteristic features include molar-tooth structures, stromatolites, flat-pebble conglomerates and stylolites, indicating deposition on a shallow to moderately deep, storm-influenced carbonate ramp under generally quiet, sub-wave-base conditions. Pb–Pb dating gives a Mesoproterozoic age of about 1.6 Ga.
