kids: Fossil Alley! - Where we're going to find ... The Law of Superposition means that when we see a stack of rock layers, the oldest rocks are usually on the bottom, and the younger ones are ...

Using the principle of faunal succession, if an unidentified fossil is found in the same rock layer as an index fossil, the two species must have existed during the same period of time (Figure 4).

A fossil is the preserved remains or traces ... This becomes buried by small particles of rock called sediment. As more layers of sediment build up on top, the sediment around the skeleton begins ...

The Canyon is a Book of Revelations in the rock-leaved Bible of geology. - John Wesley Powell A professor of geology at Illinois Wesleyan, John Wesley Powell had more than just a passing ...