| The geologic time scale, which defines geological periods, began to take its modern form only in the 19th century. |
| The first is a simplified depiction of the geologic time scale. |
| Yes, it has a season that is best measured by the geologic time scale. |
| The geologic time scale was developed based on the relative ages of rock strata as determined by the early paleontologists and stratigraphers. |
| The geologic time scale encompasses the history of the Earth. |
| A standardized geologic time scale is the framework for deciphering and understanding the long and complex history of our planet Earth. |
