Toarcian [SEP] named after
Toarcian
The Toarcian is, in the ICS' geologic timescale, an age and stage in the Early or Lower Jurassic. It spans the time between 182.7 Ma (million years ago) and 174.1 Ma. It follows the Pliensbachian and is followed by the Aalenian.
The Toarcian age began with the Toarcian turnover, the extinction event that sets its fossil faunas apart from the previous Pliensbachian age.
Stratigraphic definitions.
The Toarcian takes its name from the city of Thouars, just south of Saumur in the Loire Valley
Cleviceras
Cleviceras is an extinct genus of cephalopod belonging to the family Hildoceratidae. These cephalopods existed in the Jurassic period, during Toarcian and possibly even uppermost Pliensbachian age. Sometimes, it is considered to be a synonym of "Eleganticeras".
Etymology.
Genus is named after Cleveland, and area in north England. Fossils of "Cleviceras exaratum", type species of this genus are very abundant there.
Distribution.
Fossils of species contained in this genus have been found in the lower to middle Toarcian of