The Lilstock Formation is a

geologic formation A geological formation, or simply formation, is a body of rock having a consistent set of physical characteristics ( lithology) that distinguishes it from adjacent bodies of rock, and which occupies a particular position in the layers of rock exp ...

England England is a Countries of the United Kingdom, country that is part of the United Kingdom. It is located on the island of Great Britain, of which it covers about 62%, and List of islands of England, more than 100 smaller adjacent islands. It ...

. It preserves

bivalve Bivalvia () or bivalves, in previous centuries referred to as the Lamellibranchiata and Pelecypoda, is a class (biology), class of aquatic animal, aquatic molluscs (marine and freshwater) that have laterally compressed soft bodies enclosed b ...

insect Insects (from Latin ') are Hexapoda, hexapod invertebrates of the class (biology), class Insecta. They are the largest group within the arthropod phylum. Insects have a chitinous exoskeleton, a three-part body (Insect morphology#Head, head, ...

and other invertebrate

fossils A fossil (from Classical Latin , ) is any preserved remains, impression, or trace of any once-living thing from a past geological age. Examples include bones, shells, exoskeletons, stone imprints of animals or microbes, objects preserved ...

, as well as fossil fish of '' Agkistracanthus mitgelensis'' and the basal theropod dinosaur '' Newtonsaurus cambrensis'' dating back to the

Rhaetian The Rhaetian is the latest age (geology), age of the Triassic period (geology), Period (in geochronology) or the uppermost stage (stratigraphy), stage of the Triassic system (stratigraphy), System (in chronostratigraphy). It was preceded by the N ...

of the

Triassic The Triassic ( ; sometimes symbolized 🝈) is a geologic period and system which spans 50.5 million years from the end of the Permian Period 251.902 million years ago ( Mya), to the beginning of the Jurassic Period 201.4 Mya. The Triassic is t ...

period Period may refer to: Common uses * Period (punctuation) * Era, a length or span of time *Menstruation, commonly referred to as a "period" Arts, entertainment, and media * Period (music), a concept in musical composition * Periodic sentence (o ...

White Lias

The White lias is a rare, fine-grained form of

limestone Limestone is a type of carbonate rock, carbonate sedimentary rock which is the main source of the material Lime (material), lime. It is composed mostly of the minerals calcite and aragonite, which are different Polymorphism (materials science) ...

from the late

period, occurring only in certain parts of

Somerset Somerset ( , ), Archaism, archaically Somersetshire ( , , ) is a Ceremonial counties of England, ceremonial county in South West England. It is bordered by the Bristol Channel, Gloucestershire, and Bristol to the north, Wiltshire to the east ...

and infrequently in

Warwickshire Warwickshire (; abbreviated Warks) is a Ceremonial counties of England, ceremonial county in the West Midlands (region), West Midlands of England. It is bordered by Staffordshire and Leicestershire to the north, Northamptonshire to the east, Ox ...

. It gets the name ‘lias’ from the quarrymen's dialect for ‘layers’, referring to its natural state when quarried. White lias is part of the Langport Member of the Lilstock Formation, a multi-layered bed of stone formed from

shale Shale is a fine-grained, clastic sedimentary rock formed from mud that is a mix of flakes of Clay mineral, clay minerals (hydrous aluminium phyllosilicates, e.g., Kaolinite, kaolin, aluminium, Al2Silicon, Si2Oxygen, O5(hydroxide, OH)4) and tiny f ...

and limestone. At its base is a bone-bed yielding ancient marine, reptilian and

ammonite Ammonoids are extinct, (typically) coiled-shelled cephalopods comprising the subclass Ammonoidea. They are more closely related to living octopuses, squid, and cuttlefish (which comprise the clade Coleoidea) than they are to nautiluses (family N ...

fossils. White lias varies in colour from white-cream to pale grey and is traditionally used for building and flooring. Evidence of its use can be seen in manor houses, churches and cathedrals all over the UK. It is most prevalent in the Somerset towns of

Midsomer Norton Midsomer Norton is a town near the Mendip Hills in Bath and North East Somerset, England, south-west of Bath, Somerset, Bath, north-east of Wells, Somerset, Wells, north-west of Frome, west of Trowbridge and south-east of Bristol. It has ...

Radstock Radstock is a town and civil parish on the northern slope of the Mendip Hills in Somerset, England, about south-west of Bath and north-west of Frome. It is within the area of the unitary authority of Bath and North East Somerset. The Radsto ...

Langport Langport is a town and Civil parishes in England, civil parish in Somerset, England, west of Somerton, Somerset, Somerton. The parish, which covers only part of the town, has a population of 3,578. Langport is contiguous with Huish Episcopi, ...

and

Wincanton Wincanton ( or ) is a town and electoral ward in Somerset, southwest England. The town lies off the A303 road, a main route between London and South West England, and has some light industry. In the 2021 census the civil parish had a populatio ...

. Bowdens quarry in Langport is the only supplier of white lias, and of the more commonly found

blue lias The Blue Lias is a formation (stratigraphy), geological formation in southern, eastern and western England and parts of South Wales, part of the Lias Group. The Blue Lias consists of a sequence of limestone and shale layers, laid down in latest ...

and grey varieties.

White Lias

See also

References

Further reading