Loose material, such as dust and rock fragments, covering bedrock.

A lowering of sealevel observed in the geological record. See trangression.

The age of a rock or formation given relative to other rocks or formation, usually defined as a zone fossil name. See also Absolute age.

A local sea level change caused by a combination of global (eustatic) and local (isostatic) changes. This is the sea level variation "recorded" by the rock record.

A channel (sinuous rille) or trench like feature (linear or arcuate rille) on the surface of the Moon.

Latin word used to name rilles on the Moon (pl. rimae).

Sequence stratigraphy is a branch of geology that attempts to link relative sea-level changes to sedimentary deposits. The essence of the method is mapping of strata based on identification of time lines, such as unconformities, maximum flooding surfaces and transgression surfaces. In doing so it places stratigraphy in chronostratigraphic framework.

A geological period; the third of the Paleozoic Era from 443 to 416Ma. The fossil record from this period includes a huge variety of marine fossils, land plants and early invertebrate land animals.

Epochs:

• Prídolí 418-416Ma
• Ludlow 422-418Ma
• Wenlock 428-422Ma
• Llandovery 443-428Ma

The study of layered sedimentary or metamorphic rocks and how they related to each other, particularly their ages.

A raising of sea level observed in the geological record. See regression.