Geologic age dating sequence
First, the stratigraphic range of a fossil type is always open to extension as new fossils are discovered.Second, when an extension of a fossil's range may be required, geologists may call upon erosion (reworking fossils into younger strata or leaking fossils into older strata) and structural events (overturning or faulting strata and fossils).Therefore, a rock's physical appearance cannot, with certainty, distinguish the system or strata level to which a rock may belong.The sequence of rock types is more useful, but hardly an infallible guide to correlation.A single sedimentary lamina, or bed, was supposed by uniformitarian geologists to represent typically a year or many years duration.It was concluded, therefore, that multiplied thousands of laminae and beds superimposed required millions of years.Recently, however, geologists have discovered that laminae and beds form quickly on floodplains of rivers during floods, in shallow marine areas during storms, and in deep water by turbidity currents.
The geologic column was not composed by assembling a chronology of "periods," "eras" or other supposed measures of time, but by superposition of objectively defined sequences of sedimentary strata called "systems." The "periods" and "eras" were later appended to the system nomenclature of the "geologic Column" transforming it into a "geologic time scale." The notion that the earth's crust has on "onion skin" structure with successive layers containing all strata systems distributed on a global scale is not according to the facts.The data from oil well drilling, seismic surveys, and surface geologic mapping is of such character that subsurface correlation of lithostratigraphic units of the thickness of systems is possible on a continental scale.Although some fossils appear to be distinctive of certain systems (most fossil taxa range through a few to several systems), care must be exercised in correlation by fossils.The entire geologic column, composed of complete strata systems, exists only in the diagrams drawn by geologists!Hundreds of locations are known where the order of the systems identified by geologists does not match the order of the geologic column.