Geological dating wiki
For example, the boundary between the Cretaceous period and the Palaeogene period is defined by the Cretaceous–Tertiary extinction event.
This marked the end of the dinosaurs and of many marine species.
In the 19th century some geologists realized that the vast thicknesses of sedimentary rocks meant that the Earth must be at least hundreds of millions of years old.A form of romantic courtship typically between two individuals with the aim of assessing the other's suitability as a partner ...| An estimation of the age of an artifact, biological vestige, linguistic usage, etc. dictionary.cambridge.org/dictionary/british/date 1a social meeting planned before it happens, especially one between two people who have or might have a romantic relationship | [United States] a ...We now know the timing of important events that have happened during the history of Earth.The Earth is about 4.567 billion (4,567 million) years old.