The Shells of the Shell Grotto
- 4 days ago
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Updated: 19 hours ago
Shells have held significant spiritual, economic and practical value for different cultures throughout history. The earliest human-like species, Homo Erectus, were using freshwater mussel shells as tools around 500,000 years ago. And ancient cultures, including Egyptians, Greeks and Romans, viewed shells as symbols of fertility, protection, life, femininity and rebirth, subjects that have all been associated with the Shell Grotto as a possible theory for its use.
There are thought to be more than 50,000 species of shelled molluscs on Earth. The approximately 4.6 million shells in the Grotto are comprised of just 40 different varieties, which, with only two exceptions, are all native to Britain. This makes the Grotto unusual – other shell structures in the UK, often forming part of large estates, are worked with exotic shells, used not only for their decorative value but to demonstrate that the owner was wealthy, educated and well-travelled.
Humble blue mussels (Mytilus edulis), common cockles (Cerastoderma edule), common whelks (Buccinum undatum), common limpets (Patella vulgata), variegated scallops (Chlamys varia) and common oysters (Ostrea edulis) are some of the shells used most often, thought to have been collected from one of four local bays: Walpole Bay, Cliftonville; Pegwell Bay, Cliffsend; Sandwich Bay, Sandwich; and Shellness on the Isle of Sheppey.
The most frequently used shell, however, the flat periwinkle (Littorina obtusata), which has been used to create the background infill in between each mosaic design, is rarely found locally, instead thought to have been collected from shores west of Southampton. Unlike many of the other shells, the flat winkle is not eaten or used in any manufacturing process, so these shells, found naturally in vibrant yellows and oranges, were likely brought to Margate for their looks alone.
Both foreign shell species can be found in the Altar Chamber. Two queen conches (Strombus gigas) from the Caribbean can be seen in the upper, western corners of the chamber, while giant clams (Tridacnea crocea) from the Indo-Pacific sit atop its altar and entrance arch.
Two more queen conches once sat in the upper, eastern corners, but these were lost when the chamber’s East Wall was destroyed in 1939. If the chamber’s ceiling was originally vaulted, as has been suggested, these conches would have sat in each corner at the base of the vault. A 1987 guide of the Grotto theorised that the conches were used as a form of lamp, with the bowl of the shell holding oil and some form of wick.
The anomalous appearance of foreign shells, however, may indicate that they are not contemporary with the rest of the mosaic, perhaps added later when exotic shells became more accessible. Given that the Caribbean wasn’t discovered by Europe until 1492, it seems likely that these shells, at least, were added after the 15th century.
The only non-mollusc shells used in the Grotto - edible sea urchins (Echinus esculentis) and green sea urchins (Psammechinus miliaris) - can also be found in the Altar Chamber, in the centre of each star-shaped mosaic.
When originally embedded, all the shells would have been their natural purple, yellow and orange colours. Today, however, they appear taupe, caused by a layer of carbon deposit created by Victorian gas lamps which lit the Grotto for nearly 100 years.
Naturalist Frank Buckland (1826-1880), who visited the Grotto many times, believed that the shells were carefully assorted into sizes, washed and embedded into the mosaic while still alive, thinking that this had helped preserve them, a belief shared by our current conservator, Rob Smith. If the shells had been boiled alive directly before application, it would have created a natural animal glue to help adhere them to the wall. Some early publications reference there being several shells within the Grotto with fossilised molluscs inside, but there is no longer evidence of this.
In 1897, Frederick Stanley, member of the Conchological Society, was commissioned to write a report on the shells in the Grotto. In his report, Stanley expressed the opinion that most shells were imported from Shellness in Pegwell Bay, about 8 miles from Margate, because they didn't appear at Margate in the quantities needed.
‘The first thing that strikes me, is that with very few exceptions, and those principally of the shell-fish used as food, the great bulk of the varieties have been imported, I should say, from Shellness in Pegwell Bay; and although some of the species are found in the vicinity of Margate, they do not occur in the quantity necessary to have carried out so elaborate and extensive a piece of Shell Mosaic, unless years had been spent in their collection. Also, some of the commonest kinds found after certain winds and tides at Margate, such as "Tapes pallustra" are conspicuous by their absence.’
Of course, species quantities and habitat locations can change, but the indication is that, if the shells were collected from Margate itself, it was done a long time before Stanley's 1897 report, when species were perhaps more abundant here.
Stanley only recorded 28 different varieties of shell and did not identify the two large, international species, either because they were not present or because the light conditions were insufficient to conduct a thorough study.
A report conducted in 2012 by John Jones, lecturer and author on conchology, identified 40 species. You can read copies of the reports and a side-by-side comparison of their finds below.
Allegedly, when the Altar Chamber’s East Wall was destroyed, turtle bones were discovered secreted behind the wall – a different type of shelled creature entirely. Rumour says that this led famed science-fiction author HG Wells (1866-1946) to speculate that the Grotto was close to 3,000 years old, although there is no verifiable source for this. Unfortunately, there is also no written record of the find and the bones are no longer in the Grotto’s possession.
