The BGS Lexicon of Named Rock Units (April 2019)

The Lexicon of Named Rock Units provides definitions of lithostratigraphic, lithodemic, and litho-morpho-genetic geological units of the United Kingdom and its associated continental shelf. The Lexicon focuses mainly on units of Member, Formation, Group and higher rank (and equivalents) but it also includes information on some units of lesser rank, notably economically important coal seams and laterally extensive marine bands. It includes superficial and bedrock units. It includes synonyms and other names not currently recognised by the BGS or regarded as obsolete. Full Lexicon entries include geological unit name, a persistent unique identifier, map code, currency, rank, parent unit and rank, age, lithology, definitions of boundaries, thickness, previous and alternative names, geographical extent, type localities, and bibliographical references. This dataset is a snapshot of the live database taken on the 30th April 2019.

Glossary

Bedrock deposits: rocks, older than Quaternary age, that underlie the superficial deposits.

Litho-morpho-genetic units: geological units that are defined by their shape and mode of origin. They are generally superficial and unnamed, for example unnamed raised beach deposits, glacial moraines, and river terrace deposits.

Lithodemic units: geological units that do not obey the Law of Superposition, for example igneous intrusions and ancient highly deformed and metamorphosed terranes.

Lithostratigraphic units: geological units that obey the Law of Superposition, i.e. that are deposited in layers with the oldest at the base and the youngest at the top, for example sedimentary rocks and lava flows.

Superficial deposits: deposits of Quaternary age, generally unlithified, that overlie the bedrock.