In geology, an assise (from the French, derived from Latin assidere, "to sit beside") is two or more beds or strata of rock united by the occurrence of the same characteristic species or genera.[1] In the hierarchy of stratigraphic units, an assise lies between a stage (or sub-stage) and a stratum.[2]


  1. ^   One or more of the preceding sentences incorporates text from a publication now in the public domainChisholm, Hugh, ed. (1911). "Assise". Encyclopædia Britannica. Vol. 2 (11th ed.). Cambridge University Press. p. 782.
  2. ^ Miall, Andrew D. (2010). The Geology of Stratigraphic Sequences (2nd edition). Springer. pp. 16. ISBN 978-3-642-05026-8.