Description: This is stromatolite has a most unusual form genus. It is essentially filled with concentric spheroids called Girvanella that are commonly called algal balls. Coming from a Lower Cambrian formation, these stromatolites date to a time when stromatolites were no longer prevalent and abundant on earth. The massive cyanobacterial stromatolite reefs of the Proterozoic had yielded to new reef systems with abundant and diverse life forms. For more than two billion years the cyanobacteria had oxygenated earth’s atmosphere through their photosynthetic metabolism. Earth was now hostile to them in many ways, with other heterotrophic microbes to compete with, while the atmosphere that they had created was essentially poison to them.

We cannot say for sure that the microbes that produced these Girvanella were cyanobacteria. Perhaps they were plant-like eukaryotic algae. What seems probable is that each little spheroid was once an independent colony that was never able to grow into the large domal structures like those of Proterozoic-time.

The locality is another interesting aspect of these stromatolites. It comes from a small pod between two Ollenelus trilobite zones immediately adjacent to Area 51 near Racheal, Nevada. As we know the secrets of Area 51 are as prominent as the uncertainty of the stromatolites’ makers.

Stromatolites have persisted to the modern day in such places as Shark Bay, Australia where they continue their billions of years old lifestyle. While this piece would make a fine present for any natural history buff, anyone who appreciates art would also be glad to get thus wonderful specimen as a gift.