| Rating | Solver | Clue |
|---|---|---|
| AEON | Geological age | |
| EPOCH | Geological age | |
| EON | Geological age | |
| ERA | Geological age | |
| CENOZOIC | Belonging to the most recent division of geological time, including the tertiary, or Age of mammals, and the Quaternary, or Age of man. [Writte... | |
| ARCHAEAN | The earliest period in geological period, extending up to the Lower Silurian. It includes an Azoic age, previous to the appearance of life, and... | |
| BOVEY COAL | ... with a weak flame, and generally a disagreeable odor; -- found at Bovey Tracey, Devonshire, England. It is of geological age of the oolite, and... | |