Flo () is a historic parish (''socken'') in the Swedish province of

Västergötland Västergötland (), also known as West Gothland or the Latinized version Westrogothia in older literature, is one of the 25 traditional non-administrative provinces of Sweden (''landskap'' in Swedish), situated in the southwest of Sweden. Vä ...

. Since 1971 it has been a part of

Grästorp Municipality Grästorp Municipality () is a municipality in Västra Götaland County in western Sweden. Its seat is located in the town of Grästorp. Grästorp Municipality is located right in the middle of Västra Götaland County, by the shores of Lake Vä ...

Geology

Flo parish is the namesake for the

Floian The Floian is the second stage of the Ordovician Period. It succeeds the Tremadocian with which it forms the Lower Ordovician series. It precedes the Dapingian Stage of the Middle Ordovician. The Floian extended from to million years ago. The ...

stage, which is the second stage of the

Lower Ordovician The Early Ordovician is the first epoch of the Ordovician period, corresponding to the Lower Ordovician series of the Ordovician system. It began after the Age 10 of the Furongian epoch of the Cambrian and lasted from to million years ago, unt ...

. The base of the

is defined at the Diabasbrottet quarry type section (

GSSP A Global Boundary Stratotype Section and Point (GSSP), sometimes referred to as a golden spike, is an internationally agreed upon reference point on a stratigraphic section which defines the lower boundary of a stage on the geologic time scale. ...

) 5 km to the northwest of Flo. The base is defined in the quarry as the lowest stratigraphic occurrence of the

graptolite Graptolites are a group of colonial animals, members of the subclass Graptolithina within the class Pterobranchia. These filter-feeding organisms are known chiefly from fossils found from the Middle Cambrian ( Miaolingian, Wuliuan) through t ...

species ''

Tetragraptus approximatus ''Tetragraptus approximatus'' is a species of dichograptid graptolite belonging to the genus '' Tetragraptus''. It existed during the Floian Age ( million years ago) of the Ordovician. It is an important index fossil in biostratigraphy. Descrip ...

''.

References

{{Authority control Populated places in Västra Götaland County