Stromatolite

Within the Mineral Fork Tillite are interesting structures of layered material that are most likely a primitive fossilized organism called a stromatolite.  This sample taken from Rock Canyon shows the organic layering of the stromatolite.  This forms from layers of blue-green algae that trap or bind sediment due to the metabolic activity of these micro-organisms. (Photo by Andrew Silver)

(Sample courtesy of Hendro Nugroho)