Fact: They provide some of the oldest records for life on the planet.
The formations of stromatolites can be conical, stratiform, branching, domal, and columnar.
Not as many exist today as did in the Precambrian.
Stromatolites are formed by colonies of Cyanobacteria.
They are thought to be responsible for oxygenating the atmosphere.
They reproduce A-sexually.
Taxonomy On these is being revised.