Stromatolites

The term stromatolites is not a formal classification term. Fossil forms called stromatolites include representatives of two kingdoms. The term  refers to large, usually calcareous crusts that are similar to algal reefs. Stromatolites are classified on the how they grow and the shape of the colony.
 

There are two basic types of stromatolites: 
1..  Cryptozoon-type stromatolites; they are more hemispherical than other types and the hemispheres are depressed and may even be inverted cones (turbinate shape) and 
2.. Collenia-type stromatolites which are more finger-like than Cryptozoon types
Collenia-type stromatolite. 
Kingdom Eubacteria
Division Cyanophyta (blue-green algae)
Banded Iron Formation
Thunder Bay, Ontario, Canada
Cryptozoon type stromatolite
Kingdom Plantae
Division Chlorophycophyta. (green algae)
Chlorellopsis sp.
Green River Formation
Eocene
Douglas Pass, CO.
Cryptozoon type stromatolite
Kingdom Plantae
Division Chlorophycophyta. (green algae)
Chlorellopsis sp.
Green River Formation
Eocene


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