The principle of superposition states that the oldest sedimentary rock units are at the bottom, and the youngest are at the top.
Explanation:
The principle of superposition states that in an undeformed sequence of sedimentary rocks, each layer of rock is older than the one above it and younger than the one below it (Figures 1 and 2). Accordingly, the oldest rocks in a sequence are at the bottom and the youngest rocks are at the top.
the lowest stratum tend to have the slowest-moving creatures; above them are faster ones. Evolutionary scientists declare these lowest strata are many millions of years old (570 million for the oldest, the Cambrian), and the topmost to be the most recent.
