Paleontology seeks to map out how life evolved across geologic time.A substantial hurdle is the difficulty of working out fossil ages.Sometimes, scientists already know the age of the fossil because fossils of the same species have been found elsewhere and it has been possible to establish accurately from those when the dinosaur lived.Geologists call this the principle of lateral continuity.
Some critics, particularly religious fundamentalists, argue that neither fossils nor dating can be trusted, and that their interpretations are better.
A fossil will always be younger than fossils in the beds beneath it and this is called the principle of superposition.
In an undisturbed sequence of rocks, such as in a cliff face, it is easy to get a rough idea of the ages of the individual strata – the oldest lies at the bottom and the youngest lies at the top.
There are several different methods for estimating the ages of fossils, including: Paleontologists rely on stratigraphy to date fossils.
Stratigraphy is the science of understanding the strata, or layers, that form the sedimentary record.