Stromatolites were first identified as discrete organosedimentary structures in 1908 by Ernst Kalkowsky, Professor of Mineralogy at Dresden University. Kalkowsky recognised some Triassic sedimentary rocks from the Harz Mountains in Germany as unique; he correctly interpreted these rocks, built of thin, domed layers of sediment, as being of microbial origin. He named them stromatoliths from the Greek stroma, meaning layer and lithos meaning stone, so giving rise to the modern term stromatolite.
In this article I follow a number of authors in using the term stromatolite in the broad sense of carbonate structures constructed by benthic microbial communities, whether layered or not. Other authors use the synonymous term ‘microbialite’. I use the term thrombolite as a variety of stromatolite that is formed almost exclusively by microbially-induced precipitation, that lacks much or any internal lamination. Such stromatolites have a characteristic clotted structure.