| Algae oncolites (the oval to circular, dark nodule-like structures), genus Girvanella, from the Lower Cambrian Mule Spring Limestone, Waucoba Spring. The distinctive fossil bodies were precipitated by an extinct species of blue-green algae. |
| Algae oncolites (the oval to circular, dark nodule-like structures), genus Girvanella, from the Lower Cambrian Mule Spring Limestone, Waucoba Spring. The distinctive fossil bodies were precipitated by an extinct species of blue-green algae. |