Dating of rock layers
Scientists have determined the relative times of appearance and disappearance of many kinds of organisms from the location of their fossils within the sedimentary rock layers.” (Glenco, 1994, pp. 714.) “The procession of life was never witnessed, it is inferred.
306-307.) “No paleontologist worthy of the name would ever date his fossils by the strata in which they are found. The vertical sequence of fossils is thought to represent a process because the enclosing rocks are interpreted as a process.
Geologists have studied the order in which fossils appeared and disappeared through time and rocks. Fossils can help to match rocks of the same age, even when you find those rocks a long way apart.
This matching process is called correlation, which has been an important process in constructing geological timescales.
Many of these organisms have left their remains as fossils in sedimentary rocks.(Some of the following quotes are as cited in Morris, 1997 and Snelling, 1990).The series of quotes begins with a vivid illustration of this circular reasoning in action.This time interval was from 542-520 million years ago.This approach avoids the circularity associated with using fossils to correlate rocks, and then using those correlations to infer biological patterns…” (“Cambrian Explosion: New Timeline for Appearances of Skeletal Animals in Fossil Record,” , Nov.