Kinds of Stratotypes

Last updated:5 January 2024


The International Stratigraphic Guide gives the following definitions of various kinds of stratotypes:

  • Holostratotype: the original stratotype designated by the original author at the time of proposing a stratigraphic unit or boundary.
  • Parastratotype: a supplementary stratotype used in the original definition by the original author to illustrate the diversity or heterogeneity of the defined stratigraphic unit or some critical feature not evident or exposed in the holostratotype.
  • Lectostratotype: a stratotype for a previously described stratigraphic unit selected later in the absence of an adequately designated original stratotype (holostratotype).
  • Neostratotype: a new stratotype selected to replace an older one which has been destroyed, covered, or otherwise made inaccessible.
  • Hypostratotype: a stratotype proposed after the original designation of the holostratotype (and parastratotype) in order to extend knowledge of the unit or boundary to other geographic areas. It is always subordinate to the holostratotype.


Salvador, A (Editor) 1994, International Stratigraphic Guide: A guide to stratigraphic classification, terminology, and procedure. 2nd edition. International Union of Geological Sciences and the Geological Society of America, Boulder, Colorado.