What Is Steno's Law Of Superposition?

In the course of his research in the mountainous region of western Italy, Steno came to the conclusion that the concept of superposition in stratified (layered) rocks was the essential component in establishing a connection between time and rocks. In a nutshell, each layer of sedimentary rock, commonly referred to as a "bed," is younger than the one that is directly above it and older than the layer that is directly below it.