| The base of the Mesoproterozoic is defined chronometrically, in terms of years, rather than by the appearance or disappearance of some organism. |
| This numismatic and thus chronometrically valid distinction, however, could be useful regardless of whether the two brothers used the same or different passes. |
| Just a chronometrically perfect second – I am still in Switzerland, right? |
| With them, the ancients could accurately measure the size of the earth, map it, and chronometrically tick off the cyclic passage of the ages. |
| The new fossils are from chronometrically controlled stratigraphic sequences and date to about 4.1-4.2 million years ago. |
| All of these units except for the Ediacaran are defined chronometrically. |
