ASP159. 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. 180 mm x 150 mm x 6.5 mm thick. It weighs 369 grams.