ASP158. Fossil stromatolite slab, polished on one side.
Asperia ashburtonia from the Proterozoic "Duck Creek Dolomite".
Age is approx. 2 billion years.
From near Paraburdoo in Western Australia.
Dimensions at widest points approx. 215 mm x 100 mm x 8 mm thick. It weighs 432 grams.