David says, 'It can take millions of years, but gradually fossils become exposed at the surface where we can find them. 'Because of how they form, fossils occur in sedimentary rocks. So if you're ...

The basalt which makes up the Giant’s causeway is an igneous rock. Sedimentary rocks are formed by small rock pieces which are transported by rivers and laid down in layers. Chalk is a ...

Relative dating to determine the age of rocks and fossils Geologists have established a set of principles that can be applied to sedimentary ... strata must have formed after the rocks they ...