The layers of sedimentary rock, or strata, can be seen as horizontal bands of differently colored or differently structured materials exposed in this cliff.
The deeper layers are older than the layers found at the top, which aids in determining the relative age of fossils found within the strata. Such index fossils must be distinctive, globally distributed, and occupy a short time range to be useful.
Geologic time covers the whole sweep of earth's history, from how and when the earth first formed, to everything that has happened on, in, and to the planet since then, right up to now.
Geologists analyze geologic time in two different ways: in terms of relative geologic age, and in terms of absolute (or numeric) geologic age.
Paleontology seeks to map out how life evolved across geologic time.
A substantial hurdle is the difficulty of working out fossil ages.
It was characterized by large bifaces, particularly hand axes.
This tool-making technology was a more complex way of making stone tools than the earlier Oldowan technology.
When information derived from two outcrops is integrated, the time interval they represent is probably greater than that of each alone.The basis for assuming that like fossils indicate contemporary formation is faunal succession.However, as previously noted, times of volcanism and metamorphism, which are both critical parts of global processes, cannot be correlated by fossil content.More flakes were knocked off from both sides of a stone and there is evidence that the maker had a preconceived notion of the tool's final form.Acropolis - The "high point" or citadel of an ancient Greek city, like the Acropolis in Athens.