Bishop's Frome Limestone
Encyclopedia
The Bishop's Frome Limestone (or Bishops Frome Limestone) is a rock unit within the Raglan Mudstone Formation of the Old Red Sandstone
occurring in the border region between England
and South Wales
. This limestone is a calcrete, that is to say it originated as a soil during a break in deposition rather than than being an original marine deposit. It is perhaps the most significant of all of the calcretes which occur within the uppermost Silurian
and lower Devonian
sequence of rocks which constitute the Old Red Sandstone of the Anglo-Welsh Basin. It defines the boundary within the basin between the Silurian and the Devonian periods. The rock was formerly known as the Psammosteus Limestone after a characteristic fossil fish recorded from it; Psammosteus anglicus. The fossil remains were subsequently shown to have been wrongly identified and belong in fact to Traquairaspis symondsi. Its modern name derives from the Herefordshire
village of Bishop's Frome
. Its thickness is variable ranging from 2m up to 8m.
Old Red Sandstone
The Old Red Sandstone is a British rock formation of considerable importance to early paleontology. For convenience the short version of the term, 'ORS' is often used in literature on the subject.-Sedimentology:...
occurring in the border region between England
England
England is a country that is part of the United Kingdom. It shares land borders with Scotland to the north and Wales to the west; the Irish Sea is to the north west, the Celtic Sea to the south west, with the North Sea to the east and the English Channel to the south separating it from continental...
and South Wales
Wales
Wales is a country that is part of the United Kingdom and the island of Great Britain, bordered by England to its east and the Atlantic Ocean and Irish Sea to its west. It has a population of three million, and a total area of 20,779 km²...
. This limestone is a calcrete, that is to say it originated as a soil during a break in deposition rather than than being an original marine deposit. It is perhaps the most significant of all of the calcretes which occur within the uppermost Silurian
Silurian
The Silurian is a geologic period and system that extends from the end of the Ordovician Period, about 443.7 ± 1.5 Mya , to the beginning of the Devonian Period, about 416.0 ± 2.8 Mya . As with other geologic periods, the rock beds that define the period's start and end are well identified, but the...
and lower Devonian
Devonian
The Devonian is a geologic period and system of the Paleozoic Era spanning from the end of the Silurian Period, about 416.0 ± 2.8 Mya , to the beginning of the Carboniferous Period, about 359.2 ± 2.5 Mya...
sequence of rocks which constitute the Old Red Sandstone of the Anglo-Welsh Basin. It defines the boundary within the basin between the Silurian and the Devonian periods. The rock was formerly known as the Psammosteus Limestone after a characteristic fossil fish recorded from it; Psammosteus anglicus. The fossil remains were subsequently shown to have been wrongly identified and belong in fact to Traquairaspis symondsi. Its modern name derives from the Herefordshire
Herefordshire
Herefordshire is a historic and ceremonial county in the West Midlands region of England. For Eurostat purposes it is a NUTS 3 region and is one of three counties that comprise the "Herefordshire, Worcestershire and Gloucestershire" NUTS 2 region. It also forms a unitary district known as the...
village of Bishop's Frome
Bishop's Frome
Bishop's Frome is a village and civil parish in eastern Herefordshire, England. It is northeast of the City of Hereford, west of Malvern, Worcestershire and south of Bromyard...
. Its thickness is variable ranging from 2m up to 8m.