Hettangian

The Hettangian is the earliest age and lowest stage of the Jurassic Period of the geologic timescale.

[5] In European stratigraphy the Hettangian is a part of the time span in which the Lias was deposited.

Another example is the lower Lias from the Northern Limestone Alps where well-preserved but very rare ammonites, including Alsatites, have been found.

A global reference profile (a GSSP) for the base was defined 2010 for an exposure of the Kendlbach Formation at the Kuhjoch section in the Karwendel Mountains of western Austria.

[6] The top of the Hettangian Stage (the base of the Sinemurian) is at the first appearances of ammonite genera Vermiceras and Metophioceras.