Relative Dating: Introduction
William Smith’s Discovery
Fossils like this ammonite were so commonplace that the English used them as pound weights for their butter churns. A few scientists tried to ascertain their origin, but to most people the fossils were a mystery to which they did not give much thought. Not so for William Smith—he made an observation that would change the scientific world forever. Observing that marine fossils were found on dry land and were found in a definite order, he led scientists to believe, for the first time, that planet Earth is ancient and that its life forms have changed over time. In this section, you will learn how fossils have been an invaluable tool in helping scientists piece together a history of Earth.
