
The Shell Grotto is an ornate subterranean passageway
shell grotto
A shell grotto is a type of folly, a grotto decorated with sea shells. The shell grotto was a popular feature of many British country houses in the 17th and 18th centuries. It suited the Baroque and Rococo styles (which used swirling motifs sim ...
in
Margate
Margate is a seaside resort, seaside town in the Thanet District of Kent, England. It is located on the north coast of Kent and covers an area of long, north-east of Canterbury and includes Cliftonville, Garlinge, Palm Bay, UK, Palm Bay and W ...
,
Kent
Kent is a Ceremonial counties of England, ceremonial county in South East England. It is bordered by Essex across the Thames Estuary to the north, the Strait of Dover to the south-east, East Sussex to the south-west, Surrey to the west, and Gr ...
, England. Almost all the surface area of the walls and roof is covered in
mosaic
A mosaic () is a pattern or image made of small regular or irregular pieces of colored stone, glass or ceramic, held in place by plaster/Mortar (masonry), mortar, and covering a surface. Mosaics are often used as floor and wall decoration, and ...
s created entirely of
seashells
A seashell or sea shell, also known simply as a shell, is a hard, protective outer layer usually created by an animal or organism that lives in the sea. Most seashells are made by mollusks, such as snails, clams, and oysters to protec ...
, totalling about of mosaic, or 4.6 million shells. It was claimed to have been "discovered in 1835", but its age and purpose remain unknown. The grotto is a Grade I-
listed building
In the United Kingdom, a listed building is a structure of particular architectural or historic interest deserving of special protection. Such buildings are placed on one of the four statutory lists maintained by Historic England in England, Hi ...
and open to the public.
Overview

The Shell Grotto consists of a winding subterranean passageway, about high and in length, terminating in a rectangular room, referred to as the
Altar
An altar is a table or platform for the presentation of religion, religious offerings, for sacrifices, or for other ritualistic purposes. Altars are found at shrines, temples, Church (building), churches, and other places of worship. They are use ...
Chamber and measuring approximately .
The grotto is entirely underground. Steps at the upper end lead into a passage about wide, roughly hewn out of the chalk, which winds down in serpentine fashion until it reaches an arch, the walls and roof of which here onward are covered in with shell mosaic. The arch leads to what is known as the Rotunda, a central circular column, meeting at the farther side at the Dome - a shaft rising to the surface, capped to allow some daylight into the structure. The plan of the sub-base of the Dome is triangular, equilateral, and with an arch in the centre of each side. The two arches in the sides are those leading from the Rotunda, whilst the arch in the base leads into the Serpentine Passage. This passage, with its curving walls and over-arching vaults, is rich in mosaics of varied design.
At the end of the Serpentine Passage, a further arch leads into the Rectangular Chamber. Here the decoration takes on a more formal and geometric character, but still finely drawn and executed. The subjects are chiefly star and sun shapes. The focal point, the "altar", is the arcuate niche which faces the gothic-style entrance arch.
The purpose of the structure is unknown and various
hypotheses
A hypothesis (: hypotheses) is a proposed explanation for a phenomenon. A scientific method, scientific hypothesis must be based on observations and make a testable and reproducible prediction about reality, in a process beginning with an educ ...
date its construction to any time in the past 3,000 years. Hypotheses include: it was an 18th or 19th-century rich man’s
folly
In architecture, a folly is a building constructed primarily for decoration, but suggesting through its appearance some other purpose, or of such extravagant appearance that it transcends the range of usual garden buildings.
Eighteenth-cent ...
; it was a prehistoric astronomical calendar; it was a meeting place for sea witchcraft; and it is connected with the
Knights Templar
The Poor Fellow-Soldiers of Christ and of the Temple of Solomon, mainly known as the Knights Templar, was a Military order (religious society), military order of the Catholic Church, Catholic faith, and one of the most important military ord ...
or
Freemasonry
Freemasonry (sometimes spelled Free-Masonry) consists of fraternal groups that trace their origins to the medieval guilds of stonemasons. Freemasonry is the oldest secular fraternity in the world and among the oldest still-existing organizati ...
. Since the 2007 discovery of a domed cave under the
Palatine Hill
The Palatine Hill (; Classical Latin: ''Palatium''; Neo-Latin: ''Collis/Mons Palatinus''; ), which relative to the seven hills of Rome is the centremost, is one of the most ancient parts of the city; it has been called "the first nucleus of the ...
in Rome with shells, mosaics and marble in similar patterns to those in the Rectangular Chamber in Margate, some credence has been given to the theory that the Shell Grotto could have been created by the
Phoenicians
Phoenicians were an ancient Semitic group of people who lived in the Phoenician city-states along a coastal strip in the Levant region of the eastern Mediterranean, primarily modern Lebanon and the Syrian coast. They developed a maritime civi ...
in the second half of the first millennium BCE, when they were founding many colonies from their base in Carthage; however the gothic style of the arches would be a first for a pre 12th century arcade.
The most frequently used shells throughout the mosaic –
mussels
Mussel () is the common name used for members of several families of bivalve molluscs, from saltwater and freshwater habitats. These groups have in common a shell whose outline is elongated and asymmetrical compared with other edible clams, whic ...
, cockles,
whelks,
limpets
Limpets are a group of aquatic snails with a conical shell shape (patelliform) and a strong, muscular foot. This general category of conical shell is known as "patelliform" (dish-shaped). Existing within the class Gastropoda, limpets are a po ...
,
scallops
Scallop () is a common name that encompasses various species of marine bivalve molluscs in the taxonomic family Pectinidae, the scallops. However, the common name "scallop" is also sometimes applied to species in other closely related famili ...
, and
oysters
Oyster is the common name for a number of different families of Seawater, salt-water bivalve molluscs that live in Marine (ocean), marine or Brackish water, brackish habitats. In some species, the valves are highly Calcification, calcified, a ...
– are largely local. They could have been found in sufficient numbers from four possible bays: Walpole Bay in Cliftonville;
Pegwell Bay
Pegwell Bay is a shallow inlet in the English Channel coast astride the estuary of the River Stour north of Sandwich Bay, between Ramsgate and Sandwich in Kent. Part of the bay is a nature reserve, with seashore habitats including mudflats an ...
especially at Shellness Point,
Cliffsend
Cliffsend is a village (sometimes written, correctly, as Cliffs End) and civil parish situated almost west of Ramsgate, Kent, United Kingdom, in the Thanet local government district.
Hengist and Horsa landed near here in 410AD, and St August ...
, near Richborough; Sandwich Bay, Sandwich; and
Shellness
Shellness is a small coastal hamlet on the most easterly point of the Isle of Sheppey in the Borough of Swale in the English county of Kent. The settlement forms part of the parish of Leysdown. It is south-east of the main village of Leysdown-o ...
on the
Isle of Sheppey
The Isle of Sheppey is an island off the northern coast of Kent, England, neighbouring the Thames Estuary, centred from central London. It has an area of . The island forms part of the districts of England, local government district of Borough ...
. The majority of the mosaic is formed from the flat winkle, which is used to create the background infill between the designs. However, this shell is found only rarely locally, so could have been collected from shores west of
Southampton
Southampton is a port City status in the United Kingdom, city and unitary authority in Hampshire, England. It is located approximately southwest of London, west of Portsmouth, and southeast of Salisbury. Southampton had a population of 253, ...
, where it is abundant.
Attached to the grotto is a modern museum and gift shop.
Cultural depictions
The grotto is featured in the book Elijah's Mermaid (2012) by Essie Fox.
History
There are conflicting accounts of the grotto’s discovery, although most agree on a date of 1835. The earliest reference to the discovery appears in an article in a predecessor of the ''Kentish Mercury'' of 9 May 1838:
It has remained in private ownership ever since.
In 1932, the then new owner took over the grotto, and soon afterwards substituted electric lighting for the gas lighting that, over the decades, had blackened the once-colourful shells. Cleaning trials show that in the majority of the grotto, the shells have lost their colour under the dirt and are white.
[Shell Grotto Archive.] The structure has also suffered the effects of water penetration, though it was removed from the
Heritage at Risk Register
An annual ''Heritage at Risk Register'' is published by Historic England. The survey is used by national and local government, a wide range of individuals and heritage groups to establish the extent of risk and to help assess priorities for acti ...
in 2012 after a five-year conservation programme, carried out in partnership with
Historic England
Historic England (officially the Historic Buildings and Monuments Commission for England) is an executive non-departmental public body of the British Government sponsored by the Department for Culture, Media and Sport. It is tasked with prot ...
. A scheme to sponsor replacement mosaic panels, The Roundel Project, was established in 2012.
The Friends of the Shell Grotto was formed in 2008 and is a not-for-profit trust established to promote, conserve, and preserve the grotto as a unique historical monument.
References
Bibliography
*Nigel Barker,
Allan Marshall Brodie
Allan Brodie is a British historian and architectural historian. His expertise includes medieval ecclesiastical architecture and the history of tourism in Britain. He studied for his MA at the Courtauld Institute of Art, University of London in ...
, Nick Dermott, Lucy Jessop, and Gary Winter – ''Margate's Seaside Heritage'' (Informed Conservation series), English Heritage, 2007 ()
*Harold Bayley – ''
The Lost Language of Symbolism'', Ernest Benn Ltd, 1974 ()
*Howard Bridgewater – ''The Grotto'', Rydal Press, Keighley, Yorkshire, 1948, and Kent Archaeological Society, 3rd ed., 1957
*Dorothea Chaplin – ''Matter, Myth and Spirit'', Rider & Co, 1935 (ISBN B0000D5LFU)
*Harper Cory – ''The Goddess at Margate'', Henry Burt & Son Ltd, Bedford, 1949
*Lionel Fanthorpe and Patricia Fanthorpe – ''
The World’s Most Mysterious Places'', Hounslow Press, 1999 ()
*Ruby Haslam – ''The Shell Temple'', Regency Press, 1974
*Ruby Haslam – "The Shell Grotto at Margate", in ''Underground Mythology'', ed. by Sylvia Beamon; Able Publishing, 2002 ()
*Ruby Haslam – ''Reality and Imagery: The Grottoes of Margate and Twickenham'', Athena Press, 2009 ()
*Michael Howard – ''
Earth Mysteries'', Robert Hale, 1989 ()
*Hazelle Jackson – ''Shell Houses and Grottoes'', Shire Publications, 2001 ()
*Barbara Jones – ''Follies and Grottoes'', Constable, 1953 (ISBN B0000CINFP) and revised second edition, 1974.
*Rod LeGear – ''Underground Thanet'', Trust for Thanet Archaeology, 2012
*Patricia Jane Marsh – ''The Enigma of the Margate Shell Grotto, An examination of the theories on its origins'', Martyrs Field Publications, 2011 (), revised 2nd ed., 2015 (), and revised 3rd ed., 2020 ()
*C. A. Mitchell – ''The Grotto: A Study of One of the First Great Civilizations'', Cooper the Printer Ltd, Margate, c. 1949
*Nigel Pennick – ''The Subterranean Kingdom'', Turnstone, 1981 ()
*Conan Shaw and Nellie I. Shaw – ''The Shell Temple of Margate: An Archaic Masterpiece'', Cooper the Printer, Margate, 1954
*
Theo Vennemann
Theo Vennemann genannt Nierfeld (; born 27 May 1937) is a German historical linguist known for his controversial theories of a " Vasconic" and an " Atlantic" stratum in European languages, published since the 1990s.
He was professor of Germa ...
– "The Shell Grottoes of Thanet and Rome: Carthaginian Sanctuaries?", in ''Interdisciplinary Journal for Germanic Linguistics and Semiotic Analysis'' vol. 22, no. 1 (Spring 2017): pp. 69-110, International and Area Studies, University of California, Berkeley
External links
Official site: Shell GrottoThe Friends of the Shell GrottoHistoric England: Shell Grotto - 1341537Photos of the grottoon Flickr
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Shell grottoes
Margate
Buildings and structures in Kent
Tourist attractions in Kent
Grade I listed buildings in Kent
Grade I listed monuments and memorials
Garden design history of England