Bunter beds are
sandstoneSandstone is a sedimentary rock composed mainly of sand-sized minerals or rock grains. Most sandstone is composed of quartz and/or feldspar because these are the most common minerals in the Earth's crust. Like sand, sandstone may be any color, but the most common colors are tan, brown, yellow,...
deposits containing rounded pebbles, such as can notably be found in
WarwickshireWarwickshire is a landlocked non-metropolitan county in the West Midlands region of England. The county town is Warwick, although the largest town is Nuneaton in the far north of the county. The shape of the administrative area Warwickshire differs considerably from that of the historic county...
,
CheshireCheshire ; also known, archaically, as the County of Chester) is a ceremonial county in North West England. The traditional county town is the city of Chester, although Cheshire's largest town is Warrington. Other major towns include Congleton, Crewe, Ellesmere Port, Widnes, Runcorn, Macclesfield,...
,
StaffordshireStaffordshire is a landlocked county in the West Midlands region of England. Part of the National Forest lies within its borders...
,
NottinghamshireNottinghamshire is an English county in the East Midlands, which borders South Yorkshire, Lincolnshire, Leicestershire and Derbyshire...
,
DevonDevon is a large county in England. The county is also referred to as Devonshire, although that is an unofficial name, rarely used inside of the county itself and often indicating a traditional or historical context. The county shares borders with Cornwall to the west and Dorset and Somerset to...
and
DorsetDorset , is a county in South West England on the English Channel coast. The county town has been Dorchester since at least 1305, situated in the south of the county at . Between its extreme points Dorset measures from east to west and north to south, and has an area of...
in
EnglandEngland 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 and the North Sea to the east, with the English Channel to the south separating it from continental...
. They are thought to be alluvial deposits and, judging from the rounding of the mainly
quartziteQuartzite is a hard metamorphic rock which was originally sandstone. Sandstone is converted into quartzite through heating and pressure usually related to tectonic compression within orogenic belts...
pebbles, to have resulted from prolonged transportation in a large and turbulent river, resulting in powerful abrasion. The deposits in the
English MidlandsThe English Midlands, or the Midlands is the traditional name for the area comprising central England that broadly corresponds to the early medieval Kingdom of Mercia. It borders Southern England, Northern England, East Anglia and Wales. Its largest city is Birmingham, and it was an important...
are thought to have been transported in this way northwards from
BrittanyBrittany is a cultural and administrative region in the north-west of France. Brittany was previously a kingdom and then as a duchy it was a fief of the Kingdom of France. It was at one time called Less, Lesser or Little Britain...
,
FranceFrance , officially the French Republic , is a country located in Western Europe, with several overseas islands and territories located on other continents. Metropolitan France extends from the Mediterranean Sea to the English Channel and the North Sea, and from the Rhine to the Atlantic Ocean...
. This supposed river has been called the "Budleighensis", after the Devon village of
Budleigh SaltertonBudleigh Salterton is a small town on the south coast of Devon, England 15 miles south of Exeter. It is situated within an Area of Outstanding Natural Beauty designated East Devon AONB.- Features :...
, a site where such deposits were discovered. The depositions took place in the lower
TriassicThe Triassic is a geologic period and system that extends from about 251 to 199 Ma . As the first period of the Mesozoic Era, the Triassic follows the Permian and is followed by the Jurassic. Both the start and end of the Triassic are marked by major extinction events...
period. Some newer conglomerates, e.g. in Warwickshire, near
RytonRyton-on-Dunsmore is a village and civil parish in the Rugby district of Warwickshire, and is south-east of Coventry, England. The 2001 census recorded a population of 1,672 in the parish. The A45 dual carriageway passes through the village....
are thought to have arisen during the
Ice AgeThe general term "ice age" or, more precisely, "glacial age" denotes a geological period of long-term reduction in the temperature of the Earth's surface and atmosphere, resulting in an expansion of continental ice sheets, polar ice sheets and alpine glaciers. Within a long-term ice age, individual...
by reworking and southward transportation of older deposits by ice flows.
The
pebbleA pebble is a clast of rock with a particle size of 4 to 64 millimeters based on the Krumbein phi scale of sedimentology. It is generally considered to be larger than gravel and smaller than cobble. A rock made predominantly of pebbles is termed a conglomerate...
s, also called
cobbleCobble may refer to:* A particular size of rock, larger than gravel* Cobblestone, partially-rounded rocks used for road paving* Hammerstone, a prehistoric stone tool* Tyringham Cobble, a nature reserve in Tyringham, Massachusetts, U.S....
s, which can be used as
gravelGravel is rock that is of a specific particle size range. Specifically, it is any loose rock that is larger than two millimeters in its smallest dimension and no more than . The next smaller size class in geology is sand, which is > in size. The next larger size is cobble, which is >. Gravel can...
, as
ballastConstruction aggregate, or simply "aggregate", is a broad category of coarse particulate material used in construction, including sand, gravel, crushed stone, slag, recycled concrete and geosynthetic aggregates...
or as
cobblestoneCobblestones are stones that were frequently used in the pavement of early streets. "Cobblestone" is derived from the very old English word "cob", which had a wide range of meanings, one of which was "rounded lump" with overtones of large size...
s, are mainly milky-white quartzite but can vary in colour and composition, including some that are hard, reddish-coloured sandstone. The sandstone in which these pebbles are deposited can be used for building or as an
aggregateConstruction aggregate, or simply "aggregate", is a broad category of coarse particulate material used in construction, including sand, gravel, crushed stone, slag, recycled concrete and geosynthetic aggregates...
for
cementIn the most general sense of the word, a cement is a binder, a substance which sets and hardens independently, and can bind other materials together. The word "cement" traces to the Romans, who used the term "opus caementicium" to describe masonry which resembled concrete and was made from crushed...
or
concreteConcrete is a construction material composed of cement as well as other cementitious materials such as fly ash and slag cement, aggregate , water, and chemical admixtures...
.
The name "Bunter" derives from the
GermanGermany , officially the Federal Republic of Germany , is a country in Central Europe. It is bordered to the north by the North Sea, Denmark, and the Baltic Sea; to the east by Poland and the Czech Republic; to the south by Austria and Switzerland; and to the west by France, Luxembourg, Belgium,...
term "
BuntsandsteinThe Buntsandstein or Bunter sandstone is a lithostratigraphic and allostratigraphic unit in the subsurface of large parts of west and central Europe...
", "bunt" meaning "variegated" or "colourful", referring to the colour of the sandstone deposit, which varies from reddish to greenish. This sandstone is widespread across central Europe, notably in the
Black ForestThe Black Forest is a wooded mountain range in Baden-Württemberg, southwestern Germany. It is bordered by the Rhine valley to the west and south. The highest peak is the Feldberg with an elevation of 1,493 metres ....
and
OdenwaldThe Odenwald is a low mountain range in Hesse, Bavaria and Baden-Württemberg in Germany.- Location :The Odenwald lies between the Rhine rift with the Bergstraße and the Hessisches Ried in the west, the Main and the Bauland in the east, the Rhine-Main Plain of the Rhine rift near Darmstadt in...
region of
GermanyGermany , officially the Federal Republic of Germany , is a country in Central Europe. It is bordered to the north by the North Sea, Denmark, and the Baltic Sea; to the east by Poland and the Czech Republic; to the south by Austria and Switzerland; and to the west by France, Luxembourg, Belgium,...
.
The sandstone can be hard enough for building, yet easy enough to "work", resulting in
bridgeA bridge is a structure built to span a valley, road, body of water, or other physical obstacle, for the purpose of providing passage over the obstacle. Designs of bridges vary depending on the function of the bridge and the nature of the terrain where the bridge is constructed.-History:The first...
s,
castleA castle is a defensive structure seen as one of the main symbols of the Middle Ages. The term has a history of scholarly debate surrounding its exact meaning, but it is usually regarded as being distinct from the general terms fort or fortress, in that it describes a residence of a monarch or...
s,
cathedralA cathedral is a Christian church that contains the seat of a bishop...
s and churches constructed of reddish sandstone, throughout the relevant areas of
EuropeEurope is, by convention, one of the world's seven continents. Comprising the westernmost peninsula of Eurasia, Europe is generally divided from Asia to its east by the water divide of the Ural Mountains, the Ural River, the Caspian Sea, the Caucasus Mountains , and the Black Sea to the southeast...
(e.g. Germany,
LuxembourgLuxembourg , officially the Grand Duchy of Luxembourg , is a small, landlocked country in western Europe, bordered by Belgium, France, and Germany...
,
SwitzerlandSwitzerland , officially the Swiss Confederation , is a federal republic consisting of 26 states named cantons, with Bern as the seat of the federal authorities...
,
AlsaceAlsace is the fourth-smallest of the 26 regions of France in land area , and the smallest in metropolitan France. It is also the sixth-most densely populated region in France , with 222 inhabitants per km²...
in
FranceFrance , officially the French Republic , is a country located in Western Europe, with several overseas islands and territories located on other continents. Metropolitan France extends from the Mediterranean Sea to the English Channel and the North Sea, and from the Rhine to the Atlantic Ocean...
,
DenmarkDenmark is a Scandinavian country in Northern Europe and the senior member of the Kingdom of Denmark. It is the southernmost of the Nordic countries; southwest of Sweden and south of Norway, and it is bordered to the south by Germany. Denmark borders both the Baltic and the North Sea...
,
PolandPoland , officially the Republic of Poland , is a country in Central Europe . Poland is bordered by Germany to the west; the Czech Republic and Slovakia to the south; Ukraine, Belarus and Lithuania to the east; and the Baltic Sea and Kaliningrad Oblast, a Russian exclave, to the north...
).
The land under which these beds lie is generally very well drained, creating heathlike conditions. Because of the drainage, the soil tends to be of low fertility. A notable area in
BritainGreat Britain is an island lying to the northwest of Continental Europe. It is the ninth largest island in the world, and the largest European island. With a population of about 59.6 million people, it is the third most populated island on Earth. Great Britain is surrounded by over 1000 smaller...
, which has these characteristics, is
Cannock ChaseCannock Chase is a mixed area of countryside in the county of Staffordshire, England. The area has been designated as the Cannock Chase Area of Outstanding Natural Beauty. The Chase gives its name to the Cannock Chase local government district....
, a designated
Area of Outstanding Natural BeautyAn Area of Outstanding Natural Beauty is an area of countryside considered to have significant landscape value in England, Wales or Northern Ireland, that has been specially designated by the Countryside Agency on behalf of the United Kingdom government; the Countryside Council for Wales on...
(AONB).
The long
shingleShingle can refer to:*A flat covering element for a roof, including**Shake **Roof shingle* Shingle beach, especially in Western Europe, a beach composed of pebbles* Shingle, former name of Shingle Springs, California...
tomboloA tombolo or sometimes ayre is a deposition landform in which an island is attached to the mainland by a narrow piece of land such as a spit or bar. Once attached the island is then known as a tied island...
of
Chesil BeachChesil Beach, sometimes called Chesil Bank, in Dorset, southern England is one of three major shingle structures in Britain. Its toponym is derived from the Old English ceosel or cisel, meaning "gravel" or "shingle"....
in Dorset and the raised beach of
PortlandThe Isle of Portland is a limestone tied island, long by wide, in the English Channel. Portland is south of the resort of Weymouth, forming the southernmost point of the county of Dorset, England. Chesil Beach connects it to the mainland, and the A354 road bridge connects it to Weymouth....
, Dorset are partly composed of Bunter pebbles. As yet, no fully satisfactory and universally accepted geological explanation has been formulated to explain their precise origin and mode of transport, as each proposed theory has its difficulties.