Phanerozoic: Bubye Stromatolites...

During the Cambrian  to the early Ordovician, stromatolites remained abundant but were less diverse.  They formed in domal and stratiform geometries and are rare in columnar form.  Generally they are found in archaeocyathid bioherms, and continue in this form through out the Phanerozoic.   Since the Middle Ordovician, marine attached stromatolites are rare. They generally are found in unattached, round, laminated, stromatolitic balls.   Living stromatolite today are found in various localities, the most well known being Shark Bay, Australia and the Bahamas.

 Recent stromatolites; intertidal zone of Shark Bay, Western Australia
The two stromaolites in the front are presently growing, large stromatolite
on the left is 2m wide

Stromaolites of shark bay, dark flats in the background are covered
by algal mats

the recent...