The age of fossils can be determined using stratigraphy, biostratigraphy, and radiocarbon dating. Paleontology seeks to map out how life evolved across geologic time. A substantial hurdle is the difficulty of working out fossil ages. There are several different methods for estimating the ages of fossils, including:. Paleontologists rely on stratigraphy to date fossils. Stratigraphy is the science of understanding the strata, or layers, that form the sedimentary record.
Stratigraphic Superposition Picture on left: In places where layers of rocks are contorted, the relative ages of the layers may be difficult to determine. View near Copiapo, Chile. At the close of the 18th century, careful studies by scientists showed that rocks had diverse origins.
He assumed that the change in styles was an evolutionary one, and, if you could quantify that change, he surmised it might be used to indicate which cemeteries were older than others. Petrie's notions about Egyptology—and archaeology in general —were revolutionary. His worrying about where a pot came from, what period it dated to, and what that meant to the other objects buried with it was light-years away from the ideas represented in this photo dated to , in which "Egyptian pots" was considered enough information for the thinking man.