Geological formation
BODY OF ROCK IDENTIFIED BY LITHIC CHARACTERISTICS AND STRATIGRAPHIC POSITION; IT IS USUALLY BUT NOT NECESSARILY TABULAR AND IS MAPPABLE AT THE EARTH'S SURFACE OR TRACEABLE IN THE SUBSURFACE. SMALLER THAN A SUBGROUP
Formation (geology); Geologic formation; Geological Formation; Geologic formations; Sedimentary formation; Stratigraphic formation; Geological formations; Formation (stratigraphy)
A geological formation, or simply formation, is a body of rock having a consistent set of physical characteristics (lithology) that distinguishes it from adjacent bodies of rock, and which occupies a particular position in the layers of rock exposed in a geographical region (the stratigraphic column). It is the fundamental unit of lithostratigraphy, the study of strata or rock layers.