Name:
Collenia undosa Age: Precambrian Formation: Biwabik Formation Location: St. Louis County, Minnesota Size: Stromatolite is 5.4 inches across This specimen is not for sale Click here for similar specimens that are for sale
Here is a colorful slice of a stromatolite from the Precambrian of Minnesota. Authorities believe that stromatolites were formed by masses of green or blue-green algae, or ''cyanobacteria''. This stromatolite is from the Biwabik Formation and was found at the Mary Ellen Mine. It is believed that this stromatolite is 2.1 to 2.7 billion years old! This large stromatolite slab has been highly polished on both sides to reveal the interesting pattern of the mineral replacement. The natural coloration and unique patterns make for a striking display. This is a very pretty slice of an extremely old stromatolite.