The Law of Superposition is a fundamental principle in geology and archaeology that states that in any sequence of undisturbed sedimentary rocks, the oldest layers are at the bottom and the younger layers are at the top. This principle is crucial for understanding the relative ages of rock layers and the fossils contained within them.
The concept of superposition was first formulated by the Danish geologist Nicolas Steno in the 17th century. In his work "De solido intra solidum naturaliter contento dissertationis" (1669), Steno laid the groundwork for modern geology by describing this principle. Steno’s observations and principles, including the Law of Superposition, helped establish the foundation for understanding Earth's geological history and the formation of sedimentary rock layers.
Later geologists and paleontologists built on Steno’s work, developing the field of stratigraphy and furthering the understanding of geological processes and the age of Earth’s rocks.