The method of reading the order is called stratigraphy (layers of rock are called strata). Relative dating does not provide actual numerical dates for the rocks. Sedimentary rocks are normally laid down in order, one on top of another. In a sequence, the oldest is at the bottom, the youngest is at the top.

What is the difference between relative dating and superposition?

Superposition refers to the position of rock layers and their relative ages (Figure below). Relative age means age in comparison with other rocks, either younger or older. Superposition. The rock layers at the bottom of this cliff are much older than those at the top.