In other words, as sediment fills a depositional basins we would expect the upper most surface of the sediment to be parallel to the horizon. Subsequent layers would follow the same pattern. Image demonstrating a common use of the principle of lateral continuity Principle of Cross-Cutting tells us that the light colored granite must be older than the darker basalt dike intruding the granite.
(uncountable) A method of determining the age of a fossil by comparing its placement with that of fossils in other layers of rock. relative-adjective. WORDS NEAR relative-dating IN THE DICTIONARY.