Index fossils, also known as key, guide, or indicator fossils, are preserved remains of ancient organisms. These organisms were abundant, geographically widespread, distinctive, easily recognizable,
Smith’s law or principle of faunal succession states that sedimentary strata contain different fossils (fauna and flora) that succeed each other vertically in a specific
Unconformity in geology or Earth Science refers to a buried erosional and/or non-deposition surface separating lower older rock mass/strata and the younger upper one with
An angular unconformity occurs when rock beds above and below the unconformity lie at an angle. The younger rock beds lie flat on tilted, folded,
Nonconformity is unconformity where younger sedimentary rock beds overlie older intrusive igneous or metamorphic rocks. It is a contact plane created when younger sediments cover
A disconformity is a buried erosional or non-deposition surface or boundary between parallel rock layers of different ages. It has visible, uneven erosional surfaces and
Paraconformity in geology refers to a type of unconformity where the upper young and old lower rock layers or masses have the same orientation, i.e.,
A stratum is a rock layer with a lithology (texture, color, grain size, composition, fossils, etc.) different from the adjacent ones and several form strata.
Lithological maps are geological maps with the graphic, spatial representation of rock type, distribution, and other physical features, including that of unconsolidated surficial materials. These