Stromatolite Slab from Bolivia (with stand)

Billions of years ago, Cyanobacteria, (Blue-Green Algae) was the most abundant life form on our planet, forming in lakes, oceans, on rocks or almost anywhere there was moisture. These bacteria are credited for the creation of most of the Earth's oxygen. Over long periods of time, some of these bacteria worked its way through sand and other sediments, binding it together, dying off and then eventually transforming it into stone. That stone is known as Stromatolite, a fossilized alga and they are the oldest fossils on our planet at some 3 billion years old. Stromatolites are an example of what is called "a living fossil" as the bacteria that creates them continues to grow in several areas of our planet.