Sphaerocodium is a fossil that represents the remains of bacteria in the phylum Cyanobacteria, often called blue-green algae.
[1][2] The species of Sphaerocodium recorded by the author Rothpletz could be symbiotic intergrowths of different encrusting organisms.
Two genera (Rothpletzella and Wetheredella) were proposed in 1948 by Alan Wood to include these forms in two species from the Silurian of Gotland.
[4] Sphaerocodium is characterised by having dichotomously-branching tubular filaments made of calcite, which formed encrusting masses on objects.
Fossils of species within this genus have been found in Europe, Russia, United States, Canada, China and Australia.