Mysterious mosaic

I've mentioned before how much I love a good mystery, and there's a hell of a good one underneath the town of Margate, Kent, England.

It's called the "Shell Grotto."  It consists of a set of steps, framed by an arch, leading down into a serpentine passageway through the chalk bedrock.  Then there's a room called the "Rotunda," with a circular arched dome over walls arranged in an equilateral triangle.  This leads into a winding underground tunnel about two and a half meters high by twenty-one meters long ending in a five-by-six meter rectangular space that's been nicknamed the "Altar Chamber."

The entire thing is lined by mosaics made out of seashells.

4.6 million of them.

Looking up into the Rotunda [Image is in the Public Domain]

The mosaic designs are constructed from the shells of mussels, cockles, whelks, limpets, scallops, and oysters, all relatively common in nearby bays.  They feature patterns appearing to be stylized suns and stars, floral motifs, and some purely geometric or abstract designs.

A detail from one of the mosaics [Image licensed under the Creative Commons Emőke Dénes, Shell Grotto, Margate, Kent 3 - 2011.09.17, CC BY-SA 4.0]

The Shell Grotto was discovered when the entrance was stumbled upon in 1835, and immediately became a sensation.  The West Kent Advertiser newspaper wrote the following in 1838 (which also should have taken first place in the Run-On-Sentence of the Year Contest):

Belle Vue cottage, a detached residence, has been lately been purchased by a gentleman, who, having occasion for some alterations, directed the workmen to excavate some few feet, during which operation the work was impeded a large stone, the gentleman being immediately called to the spot, directed a minute examination, which led to the discovery of an extensive grotto, completely studded with shells in curious devices, most elaborately worked up, extending an immense distance in serpentine walks, alcoves, and lanes, the whole forming one of the most curious and interesting sights that can possibly conceived, and must have been executed by torch light; we understand the proprietor intends shortly to open the whole for exhibition, at small charge for admission.

No one in the area had any memory of who had built it and why, so this opened up the floodgates for speculation.  Historian Algernon Robertson Goddard, writing in 1903, listed the possibilities as follows:

• a seventeenth- or eighteenth-century rich person's "folly"
• a prehistoric calendar
• a meeting place for "sea witches" (whoever those might be)
• something connected to the Knights Templar

This last one made me snort-laugh, because there's a general rule that if there's something mysterious and you want to make it more mysterious, throw in the Templars.  Umberto Eco riffed on this theme in his brilliant, labyrinthine novel Foucault's Pendulum, when he had his character Jacopo Belbo explaining to the main character (Casaubon) the difference between cretins, fools, morons, and lunatics:

A lunatic is easily recognized.  He is a moron who doesn't know the ropes.  The moron proves his thesis; he has a logic, however twisted it may be.  The lunatic, on the other hand, doesn't concern himself at all with logic; he works by short circuits.  For him, everything proves everything else.  The lunatic is all idée fixe, and whatever he comes across confirms his lunacy.  You can tell him by the liberties he takes with common sense, by his flashes of inspiration, and by the fact that sooner or later he brings up the Templars.

Be that as it may, we still don't know who built the Shell Grotto.  There are also extensive shell mosaics that were created by the Romans and the Phoenicians, but the archways in the Rotunda have impressed archaeologists as being more consistent with those used in twelfth-century Gothic cathedrals (although not nearly as large, obviously), and therefore not nearly old enough to be Roman or Phoenician in origin.  It seems like the simplest thing to do would be to carbon date one of the shell fragments -- mollusk shells are largely calcium carbonate, so it should be possible -- but the site is under private ownership, and to my knowledge no one has done that yet.

So the Shell Grotto remains mysterious.  It certainly represents an enormous amount of skill and dedication, whoever created it; just cutting a tunnel that long through chalk bedrock would take extensive and back-breaking labor, not to mention then hauling over four million shells there and somehow getting them to adhere to the walls in beautiful and flowing artistic patterns.  It's open for visits from the public, and next time I'm in England I'd love to check it out.  Just another reason to travel to a country I love -- as if I needed another one.

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