Here is a beautiful slice of a stromatolite from the Tertiary of Australia. Authorities believe that stromatolites were formed by masses of green or blue-green algae, or ''cyanobacteria''. This Oncolite stromatolite is from Shark Bay and was only found recently. This stromatolite slab has been sliced to reveal the interesting pattern of the mineral replacement. The natural coloration and unique patterns make for a striking display. This is a very collectible example of an extremely unusual stromatolite.