The working definition of the base of the Kimmeridgian Stage is the base of the the Subboreal baylei ammonite Zone (in particular the base of the Pictonia flodigarriensis horizon, which is also marked by the appearance by the oldest Boreal Plasmatites). This horizon, where it occurs in the Staffin Bay section on the Isle of Skye, Scotland, UK, has been agreed by the working group as the candidate GSSP.

A formal proposal is expected in 2016/17 as detailed in the latest report of the Kimmeridgian working group (Wierbowski 2015).

The convenor of the Kimmeridgian Working Group is Andrzej Wierzbowski, Polish Geological Institute – National Research Institute, Rakowiecka 4, 00-975 Warsaw, Poland, e-mail: andrzej.wierzbowski[AT]