Domerian Stage
Domerian Stage
(named after Domero Mountain in the Lombard Alps), the fifth stage from the bottom of the Jurassic system and part of its lower series (Lias). The Domerian stage was identified by the Italian geologist G. Bonarelli in 1894. A typical deposit of this stage is composed of limestones with cherts and black shales rich in ammonites. In Western Europe it is divided into the zones Amaltheus margaritatus and Pleuroceras spinatum. The Domerian state is often viewed as the upper substage of the Pliensbachian stage.