The Northampton Sand Formation, sometimes called the Northamptonshire Sand, is a Middle

Jurassic The Jurassic ( ) is a geologic period and stratigraphic system that spanned from the end of the Triassic Period million years ago (Mya) to the beginning of the Cretaceous Period, approximately Mya. The Jurassic constitutes the middle period of ...

geological formation which is placed within the

Inferior Oolite Group The Inferior Oolite is a sequence of Jurassic age sedimentary rocks in Europe. It was deposited during the Middle Jurassic.Weishampel, David B; et al. (2004). "Dinosaur distribution (Middle Jurassic, Europe)." In: Weishampel, David B.; Dodson, Pet ...

. It was formerly worked extensively in

Northamptonshire Northamptonshire (; abbreviated Northants.) is a county in the East Midlands of England. In 2015, it had a population of 723,000. The county is administered by two unitary authorities: North Northamptonshire and West Northamptonshire. It is ...

for its

ironstone Ironstone is a sedimentary rock, either deposited directly as a ferruginous sediment or created by chemical replacement, that contains a substantial proportion of an iron ore compound from which iron (Fe) can be smelted commercially. Not to be con ...

. The Northampton Sand Formation constitutes the lowest part of the

and lies on the upper Lias clay. It attains a maximum thickness of up to to the north and west of Northampton where it lies in a subterranean basin. In the south, it fades out around

Towcester Towcester ( ) is an affluent market town in Northamptonshire, England. It currently lies in West Northamptonshire but was the former administrative headquarters of the South Northamptonshire district council. Towcester is one of the olde ...

. Northward from the edge of the basin in the upper Lias, under Northampton, it lies progressively lower beneath the

Lincolnshire limestone The Lincolnshire Limestone Formation is a geological formation in England, part of the Inferior Oolite Group of the (Bajocian) Middle Jurassic strata of eastern England. It was formed around 165 million years ago, in a shallow, warm sea on the ma ...

s. A little to the north of Corby Glen () it is at about from the surface. It fades out under north

Lincolnshire Lincolnshire (abbreviated Lincs.) is a Counties of England, county in the East Midlands of England, with a long coastline on the North Sea to the east. It borders Norfolk to the south-east, Cambridgeshire to the south, Rutland to the south-we ...

as the strata rise towards the Market Weighton Axis. The formation to dates to the

Aalenian The Aalenian () is a subdivision of the Middle Jurassic Epoch/Series of the geologic timescale that extends from about 174.1 Ma to about 170.3 Ma (million years ago). It was preceded by the Toarcian and succeeded by the Bajocian. Stratigraphi ...

, and predominantly consists of sandy

, which when freshly exposed is greenish-grey in colour, which weathers to limonitic brown

sandstone Sandstone is a clastic sedimentary rock composed mainly of sand-sized (0.0625 to 2 mm) silicate grains. Sandstones comprise about 20–25% of all sedimentary rocks. Most sandstone is composed of quartz or feldspar (both silicates ...

. It formed in an extensive, shallow sea on the northwestern margin of the London-Brabant Massif.

Dinosaur Dinosaurs are a diverse group of reptiles of the clade Dinosauria. They first appeared during the Triassic period, between 243 and 233.23 million years ago (mya), although the exact origin and timing of the evolution of dinosaurs is t ...

remains are among the fossils that have been recovered from the formation, although none have yet been referred to a specific

genus Genus ( plural genera ) is a taxonomic rank used in the biological classification of living and fossil organisms as well as viruses. In the hierarchy of biological classification, genus comes above species and below family. In binomial nom ...

.Weishampel, David B.; Dodson, Peter; and Osmólska, Halszka (eds.): The Dinosauria, 2nd, Berkeley: University of California Press . pp. 517-607. A species of

horseshoe crab Horseshoe crabs are marine and brackish water arthropods of the family Limulidae and the only living members of the order Xiphosura. Despite their name, they are not true crabs or crustaceans: they are chelicerates, most closely related to ar ...

, '' Mesolimulus woodwardi'' has been described from the formation.

Commercial exploitation

There is a description of the twentieth century exploitation of the Northampton Sand for iron-smelting in the

Wellingborough Wellingborough ( ) is a large market and commuter town in the unitary authority area of North Northamptonshire in the ceremonial county of Northamptonshire, England, 65 miles from London and from Northampton on the north side of the River Nen ...

article.

References

Bibliography

*Kent, P. & Gaunt, G.D. ''British Regional Geology Eastern England to The Wash'' (1980) *Hains, B.A. & Horton, A. ''British Regional Geology Central England'' (1969) *British Geological Survey ''1:50 000 Series. Stamford. Sheet 157'' Solid & Drift Edition (1978) Aalenian Stage Jurassic System of Europe {{UK-geologic-formation-stub

Commercial exploitation

See also

References

Bibliography