Formation: Biwabik Formation
Location: St. Louis County, Minnesota
Size: Fossil is 7.3 inches across
This is a very large slab of a stromatolite, Collenia undosa, from the Precambrian of Minnesota. Authorities believe that stromatolites were formed by masses of green or blue-green algae, or ''cyanobacteria''. This stromatolite has been estimated to be 2.1 to 2.7 billion years old! This thick slab has been highly polished on both sides. The pattern of mineral replacement is quite distinct, and the unique coloration makes for a striking display. This is a nice, large slab of this extremely old stromatolite from Minnesota.
A Certificate of Authenticity from EXTINCTIONS is included with this specimen.