You searched for: “geological horizon
geological horizon, geologic horizon
1. A layer of rock with a particular composition; especially, of fossils, used for dating the stratum.
2. A specific layer, or stratum, of soil or subsoil in a vertical cross section of land.
3. A term used to describe an artifact, art style, or other such cultural trait which has extensive geographical distribution but a limited time span.
4. A thin bed or surface within a sedimentary sequence which represents a particular portion of geologic time and that is characterized by its distinctive fossil content or lithology.