Dinocochlea: the mysterious spiral of Hastings

Spiral structures in nature hold a particular fascination on account of their beautiful yet twisted symmetry. The logarithmic spiral coiling of ammonite shells and rams’ horns, the corkscrew helix of a plant tendril, and the planar spiral of a hurricane when viewed from space, all have an aesthetic appeal beyond that of simpler geometrical shapes.

The site in Hastings, as it appears, today where Dinocochlea was discovered during road construction in 1921.

When huge spiral objects were unearthed during road construction in Hastings, almost one hundred years ago, it was not surprising that they attracted the immediate attention of geologists. To this day, the origin of these spirals from the Lower Cretaceous Wadhurst Clay is a puzzle. The story is as follows.

History of the find

In 1921, St Helens Road in Hastings (now the A2101) was extended westerly to meet up with Seddlescombe Road North (now the A21), thereby providing a bypass to Hastings town centre. Close to Old Roar Glen (a well-known local beauty spot) the workmen excavated a shallow cutting and came across some huge spiral structures lying horizontally in the rock.

The engineer in charge of the roadworks immediately notified the Hastings Museum. Those specimens not already bagged as rockery stones by local inhabitants were sent to Dr Arthur Smith Woodward, Keeper of Geology at the British Museum (Natural History), the modern Natural History Museum in South Kensington.

Smith Woodward was a distinguished fossil fish expert and an unwitting victim of the infamous Piltdown Man fraud, a faked, composite fossil that he christened Eoanthropus dawsoni. Charles Dawson, to whom the species was dedicated, is now generally thought to have been the perpetrator of the fraud, although some have claimed that he had an accomplice, with the Hastings jeweller, WJ Lewis Abbott, being among those suspected. It turns out that Lewis Abbott also knew of the giant spirals from Hastings. In an unpublished manuscript, he noted an earlier discovery of similar spirals in the nearby Hollington Quarry where, around 1900, quarry workers told him they had unearthed “a cork-screw as big as my leg”. Indeed, some of the fragments collected in 1921 were obtained through Lewis Abbott, as a label still glued to one clearly demonstrates.

Described as a snail

To return to the main theme of the story, Smith Woodward invited a colleague at the BM(NH) to describe the Hastings spirals. He chose the unrelated Bernard Barham Woodward, who had recently retired as head librarian at the BM(NH) and was a specialist on molluscs. With the aid of Smith Woodward’s renowned preparator, Mr LE Parsons, BB Woodward set about developing the specimens and reconstructing the spirals from the available fragments.

Fig. 2Fig. 2. BB Woodward, former head librarian at the British Museum (Natural History), who described Dinocochlea as a gigantic gastropod.

The largest reconstructed specimen measured a massive 7 feet 3 inches in length, was up to 14 inches in width and comprised 23 whorls forming a corkscrew (or helicospiral) reminiscent of a high-spired gastropod shell. Indeed, BB Woodward was so convinced of its identity as a gastropod that, in 1922, he formally named it Dinocochlea ingens, the genus name meaning ‘terrible snail’. Woodward believed Dinocochlea to be the largest gastropod ever to have lived – by comparison, the biggest recent gastropod shell is less than half its length, measuring a paltry 73cm. So striking was Dinocochlea ingens that it was exhibited in the public galleries of the BM(NH) during the second quarter of the 20th century. And it has recently made an appearance in a coffee-table book of treasures of the Natural History Museum.

Not a snail

It was not long before the identity of Dinocochlea as a gastropod begun to be questioned. Another mollusc specialist at the BM(NH), LR Cox, published two articles showing quite convincingly that the giant spirals were not fossil gastropods. For one thing, there is no sign of a shell and no fissures between the whorls as would be expected if the original shell had dissolved. Furthermore, some of the spirals are right-handed (dextral) while others are left-handed (sinistral). This is not usually the case for snails in which particular species have either dextral or, less commonly, sinistral shells. The large diameter of the apex also contrasts with true snails whose shells come to a point representing the tiny larval shell. The opposite end was rounded, the last whorl without any sign of a shell aperture. In addition, the coiling of Dinocochlea does not show the mathematical regularity characteristic of most gastropods. However, the most obvious objection to its identification as a gastropod is the enormous size of Dinocochlea in comparison with gastropods. It is inconceivable that so huge a gastropod should not have had a thick shell near its aperture.

Fig. 3. As once exhibited at the British Museum (Natural History), a plaster reconstruction of the largest Dinocochlea specimen, over 2 metres tall, flanked by the real apical whorl of this specimen (left) and a second specimen (right) that is coiled sinistrally, in the opposite direction to the large example.

An enormous coprolite?

An alternative theory for the origin of Dinocochlea is that it is a giant coprolite – fossilized excrement. Two pieces of evidence seem to favour this idea. Firstly, spiral coprolites are quite common, many due to the spiral valve that forms part of the digestive tract of sharks. Secondly, Hollington Quarry, where the first examples of Dinocochlea were noticed, is a locality yielding bones and teeth of the dinosaur Iguanodon. However, neither sharks nor dinosaurs could have produced excrement as large in size or as perfect in shape as Dinocochlea.

Fig. 4. Apical whorl of the large dextral specimen of Dinocochlea.

A concretion?

Others have suggested that Dinocochlea is simply a concretion, an inorganic pseudofossil. For example, it is described this way in the standard reference work Treatise on Invertebrate Paleontology. In fact, conventional concretions were found in association with Dinocochlea at the road extension site, and one of the Dinocochlea specimens was said by Woodward to be “attached to a concretionary mass of rock”. A problem with the concretion hypothesis is what process of inorganic concretion growth could produce an almost perfect helical shape?

Fig. 5Fig. 5. The sinistral specimen of Dinocochlea.

References

Cox, L.R. 1929. A spiral puzzle. Natural History Magazine 2(9), 16-27.

Cox, L.R. 1935. The Hastings giant spirals. The Hastings and East Sussex Naturalist 5, 62-68.

Paterson, V. 2008. Treasures of the Natural History Museum. Natural History Museum, London, 256 pp.

Thomas, H.D. 1935. On Dinocochlea ingens B.B. Woodward and other spiral concretions. Proceedings of the Geologists’ Association 46, 1-17.

Woodward, B.B. 1922. On Dinocochlea ingens, n. gen. et sp., a gigantic gastropod from the Wealden Beds near Hastings. Geological Magazine 59, 242-248.


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