Hertfordshire puddingstone - AbsoluteAstronomy.com

Hertfordshire puddingstone is a conglomerate

Conglomerate (geology)

A conglomerate is a rock consisting of individual clasts within a finer-grained matrix that have become cemented together. Conglomerates are sedimentary rocks consisting of rounded fragments and are thus differentiated from breccias, which consist of angular clasts...

sedimentary rock

Sedimentary rock

Sedimentary rock are types of rock that are formed by the deposition of material at the Earth's surface and within bodies of water. Sedimentation is the collective name for processes that cause mineral and/or organic particles to settle and accumulate or minerals to precipitate from a solution....

composed of rounded flint

Flint

Flint is a hard, sedimentary cryptocrystalline form of the mineral quartz, categorized as a variety of chert. It occurs chiefly as nodules and masses in sedimentary rocks, such as chalks and limestones. Inside the nodule, flint is usually dark grey, black, green, white, or brown in colour, and...

pebbles cemented together by a younger matrix

Matrix (geology)

The matrix or groundmass of rock is the finer grained mass of material in which larger grains, crystals or clasts are embedded.The matrix of an igneous rock consists of finer grained, often microscopic, crystals in which larger crystals are embedded. This porphyritic texture is indicative of...

of silica quartz

Quartz

Quartz is the second-most-abundant mineral in the Earth's continental crust, after feldspar. It is made up of a continuous framework of SiO4 silicon–oxygen tetrahedra, with each oxygen being shared between two tetrahedra, giving an overall formula SiO2. There are many different varieties of quartz,...

. The distinctive rock is largely confined to the English

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...

county of Hertfordshire

Hertfordshire

Hertfordshire is a ceremonial and non-metropolitan county in the East region of England. The county town is Hertford.The county is one of the Home Counties and lies inland, bordered by Greater London , Buckinghamshire , Bedfordshire , Cambridgeshire and...

but small amounts occur throughout the London Basin

London Basin

The London Basin is an elongated, roughly triangular sedimentary basin approximately long which underlies London and a large area of south east England, south eastern East Anglia and the adjacent North Sea...

. Despite a superficial similarity to concrete

Concrete

Concrete is a composite construction material, composed of cement and other cementitious materials such as fly ash and slag cement, aggregate , water and chemical admixtures.The word concrete comes from the Latin word...

it is entirely natural. Like other puddingstone

Puddingstone (rock)

Puddingstone, also known as either Pudding stone or Plum-pudding stone, is a popular name applied to a conglomerate that consists of distinctly rounded pebbles whose colors contrast sharply with the color of the finer-grained, often sandy, matrix or cement surrounding them...

s, it derives its name from the manner in which the embedded flints resemble the plums in a Christmas pudding

Christmas pudding

Christmas pudding is a pudding traditionally served on Christmas Day . It has its origins in medieval England, and is sometimes known as plum pudding or plum duff, though this can also refer to other kinds of boiled pudding involving dried fruit.-Basics:Many households have their own recipe for...

.

The flints were eroded from the surrounding chalk

Chalk

Chalk is a soft, white, porous sedimentary rock, a form of limestone composed of the mineral calcite. Calcite is calcium carbonate or CaCO3. It forms under reasonably deep marine conditions from the gradual accumulation of minute calcite plates shed from micro-organisms called coccolithophores....

beds some 56 million years ago in the Eocene

Eocene

The Eocene Epoch, lasting from about 56 to 34 million years ago , is a major division of the geologic timescale and the second epoch of the Paleogene Period in the Cenozoic Era. The Eocene spans the time from the end of the Palaeocene Epoch to the beginning of the Oligocene Epoch. The start of the...

epoch and were transported by water action to beaches, where they were rounded by wave erosion

Erosion

Erosion is when materials are removed from the surface and changed into something else. It only works by hydraulic actions and transport of solids in the natural environment, and leads to the deposition of these materials elsewhere...

and graded by size. A lowering of sea level

Sea level

Mean sea level is a measure of the average height of the ocean's surface ; used as a standard in reckoning land elevation...

s and general drying during a brief arid

Arid

A region is said to be arid when it is characterized by a severe lack of available water, to the extent of hindering or even preventing the growth and development of plant and animal life...

period known as the Paleocene–Eocene Thermal Maximum drew out silica from surrounding rocks into the water immersing the flint pebbles. Further drying precipitated the silica which hardened around the pebbles, trapping them in the matrix.

Puddingstone is rarely found in situ

In situ

In situ is a Latin phrase which translated literally as 'In position'. It is used in many different contexts.-Aerospace:In the aerospace industry, equipment on board aircraft must be tested in situ, or in place, to confirm everything functions properly as a system. Individually, each piece may...

in the strata but its hardness has preserved loose rocks and boulders commonly found in river beds, and less frequently exposed at the surface. A well researched outcrop lies at Colliers End near Ware.

Oxides of iron

Iron oxide

Iron oxides are chemical compounds composed of iron and oxygen. All together, there are sixteen known iron oxides and oxyhydroxides.Iron oxides and oxide-hydroxides are widespread in nature, play an important role in many geological and biological processes, and are widely utilized by humans, e.g.,...

were also trapped in the silica matrix, giving rise to many different hues when the puddingstone is examined closely. From a greater distance, puddingstone is generally brown or ginger in colour, although pink is possible. The density of flint inclusions shows notable variation between specimens.

The silica is very hard, which led to use being made of puddingstone as an auxiliary building material supplementing flintstone buildings such as St Mary's Church, Stocking Pelham

Stocking Pelham

Stocking Pelham is a village and civil parish in Hertfordshire, England. The village is one of the Pelhams, along with Brent Pelham and Furneaux Pelham.The village has a church, and did have a pub called the Cock, which burned down in February 2008...

; as a decorative feature or waymark in Hertfordshire villages, such as at Watton-at-Stone

Watton-at-Stone

Watton-at-Stone is a village in the English county of Hertfordshire, situated midway between the towns of Stevenage and Hertford in the valley of the River Beane. The 2001 census showed a population of 2,272, living in 921 households...

; or, during Roman times

Roman Britain

Roman Britain was the part of the island of Great Britain controlled by the Roman Empire from AD 43 until ca. AD 410.The Romans referred to the imperial province as Britannia, which eventually comprised all of the island of Great Britain south of the fluid frontier with Caledonia...

, for grinding corn. A fragment of a quern stone made from puddingstone, has recently been found by archaeologist Dominic Shelley on the site of a Romano-British farmstead in Great Eversden, Cambridgeshire.
Hertfordshire puddingstone was credited in local folklore

Folklore

Folklore consists of legends, music, oral history, proverbs, jokes, popular beliefs, fairy tales and customs that are the traditions of a culture, subculture, or group. It is also the set of practices through which those expressive genres are shared. The study of folklore is sometimes called...

with several supernatural

Supernatural

The supernatural or is that which is not subject to the laws of nature, or more figuratively, that which is said to exist above and beyond nature...

powers, including being a protective charm

Amulet

An amulet, similar to a talisman , is any object intended to bring good luck or protection to its owner.Potential amulets include gems, especially engraved gems, statues, coins, drawings, pendants, rings, plants and animals; even words said in certain occasions—for example: vade retro satana—, to...

against witchcraft

Witchcraft

Witchcraft, in historical, anthropological, religious, and mythological contexts, is the alleged use of supernatural or magical powers. A witch is a practitioner of witchcraft...

. Parish records from the village of Aldenham

Aldenham

This article is about the village in Hertfordshire. For the London Transport Bus Overhaul Works, see Aldenham Works.Aldenham is a village and civil parish in Hertfordshire, approx. three miles north-east of Watford and two miles from Radlett. It was mentioned in the Domesday Book and is one of...

relate that in 1662 a woman suspected of having been a witch was buried with a piece of it laid on top of her coffin to prevent her from escaping after burial. In living memory a piece of Pudding Stone was given to a bride and groom, possibly as a fertility symbol.

See also