Limestone stromatolite

Limestone stromatolite

Stromatolitic dolomitic limestone

Biogenous sedimentary rock.
Dolomitic limestone displaying fossil algal stromatolite structure. A stromatolite is a calcareous mound built up of layers of lime-secreting cyanobacteria and trapped sediment.
Devonian, Darby Formation, Wind River Mountains near Dubois, Wyoming.
https://gotbooks.miracosta.edu/rocks/sedimentary/19.html 2/2/2021