Walk that Changed History: New evidence about the discovery of the Iguanodon

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Martin Simpson (UK)

Newly unearthed documentary evidence substantiates the classic story that Mary Ann Mantell found some worn down Iguanodon teeth in Cuckfield, Sussex, before 1822 in some rocks by the roadside, while her husband Gideon was elsewhere. She was accompanied by a friend and purchased the specimens from a workman. We now have the who, what, where and why in this discovery, but the precise when remains unclear. It is suggested in this article that the event took place on 21 May 1821 and the fossils were passed to Gideon the following day. Subsequently, the ‘later to be’ dinosaur was formally named in 1825.


One of the benefits of the government’s 2020 social lockdown policy, introduced to combat the spread of the Coronavirus pandemic, has been the increase in reading, researching and publishing amongst many scientific academics. There will no doubt be a corresponding increase in productivity for the individual scientists themselves and a forthcoming ‘paper boom’. In my own case, I have spent proportionately more of my time preparing, cataloguing and researching fossils, and less on actual field collecting due to the travel restrictions, resulting in a significant catch-up of jobs that needed doing, but were otherwise confined to the back burner. In particular, with precious little television worth watching, I have been trawling the internet in search of obscure references to check the synonymies of umpteen species of interest, and to add to their historical background.

Whilst googling a topic somewhat off at a tangent from my main field of interest, and experimenting with endless word-search combinations to pass the time, on 11 May 2020 at 10pm I came across something completely unexpected, previously overlooked and hugely significant.

We have a provincial genealogist to thank for posting an article online about some early nineteenth-century inhabitants of a quintessentially English country village called Cuckfield, in the sleepy and picturesque county of West Sussex. In his blog. Cuckfield Connections, a personal journey of discovery, Mr Andy Revell has shone new light upon a story of immense importance to those interested in the history of palaeontology, in particular the study of dinosaurs. This is because one of the characters referred to is Mary Ann Mantell, wife of the famous surgeon and fossil collector, Gideon Algernon Mantell, a pioneer of Cretaceous palaeontology (Figs. 1 and 2).

Fig. 1. (Left) Mary Ann Mantell (1795-1869) and (Right) her husband Gideon Algernon Mantell (1790-1852).
Fig. 2a. Mary Ann Mantell, circa 1850s. Oil painting, artist unknown, in the collection of the Alexander Turnbull Library, Auckland, New Zealand.
Fig. 2b. Mary Ann Mantell, circa 1860s. Previously unpublished photograph in the collection of the Alexander Turnbull Library, Auckland, New Zealand. (Alexander Turnbull Library, PA10-027_BW_adjusted.tif.)

The traditional story

There is an often-told story in palaeontology of how, in the early 1820s, the first fossilised teeth were found of a creature later to be named Iguanodon, a giant terrestrial ‘saurian’ or reptile. This was later still to be included in a select group of creatures, christened the Dinosauria by Richard Owen in 1842.

Fig. 3. Typical popular account of the story of the discovery of the Mantells’ Iguanodon teeth, from the Dinosaur! magazine (Anon 1992).

The traditional version of this tale, endlessly repeated in dinosaur books, articles and magazines across the world (for example, Fig. 3), is that Mrs Mantell was out walking by the roadside while her husband Gideon was attending a patient in Cuckfield (Fig. 4), and that she happened to come across (in a pile of rubble) some unusual fossilised wedge-shaped teeth (Fig. 6a and b).

Fig. 4. Locality map showing the sites around the Mantells’ home town of Lewes in Sussex; Cuckfield, the site of the discovery; and Sheffield Park and Fletching, visited by the Mantells in 1821.

Upon seeing these specimens, so the story goes, Gideon realised that the worn down and ostensibly mammal-like teeth belonged instead to a giant herbivorous reptile, a creature new to science which, in February 1825 (Mantell, 1825), he formally named Iguanodon (Fig. 5).

Fig. 5. Restoration of Iguanodon, as redrawn by contemporary palaeo-artist Diego Barletta, after the original version of Neave Parker and adjusted for a quadrupedal posture.

Despite opposition from sceptical fellow palaeontologists, and with only a few teeth and bones to go on, Mantell (it is traditionally said) stubbornly stood by his vision of a massively scaled up version of an Iguana lizard, whose teeth his new species superficially resembled (Fig. 6c).

Fig. 6a. Iguanodon tooth. Worn down example in the Te Papa Museum, New Zealand, noted by Gideon as being the first, donated by the Mantell family in 1930.
Fig. 6b. Iguanodon tooth from Cuckfield, another of the first, wedge-shaped specimens, now in the collection of the Natural History Museum, London.
Fig. 6c. Teeth of a modern Iguana lizard, which bear a superficial resemblance to the unworn teeth of Iguanodon.

He had been aided by the opinion not only of the highly respected anatomist Baron Georges Cuvier of the Natural History Museum in Paris, to whom Gideon had sent the fossils, but also of Samuel Stutchbury of the Hunterian Museum in London, who had fortuitously provided for comparison a modern Iguana specimen from Barbados.

The rest, as they say, is history, or in this case palaeontology, and Mantell took his place amongst the greats of Victorian academia, scientists like Richard Owen, William Buckland, Charles Lyell and Roderick Murchison. Countless genera and species have been erected in Mantell’s honour and his name is entrenched in the history of dinosaur research. As others have put it, the “Wizard of the Weald” rode on the back of his “pet” Iguanodon into the “Temple of Immortality” (see Curwen 1940, p.72).

However, it is the first part of this story that deserves more scrutiny here – in particular, just who really did find these first teeth and what were the exact circumstances of their discovery?

A shift in opinion

In recent years, some scholars have cast doubt on the veracity of the original story and the role played by Mary, suggesting that the teeth were found instead by her husband, a local quarry worker or an intermediary. Scepticism was in evidence in the 1980s when Iguanodon specialist David Norman (1985), for example, described the tale as “rather appealing but unsubstantiated”. Mantell’s most notable recent biographer, Dennis Dean, later argued (Dean 1998, 1999) that the story never took place at all and is therefore fictitious, despite having been endorsed by such eminent earlier dinosaur historians as Edwin Colbert (1971) and William Stinton (1972), and also the biographer Sydney Spokes (1927, p.18).

This view has been followed by many subsequent authors, for example, MacGowan (2002: “a wonderful story without foundation”), Sarjeant (1997: “a charming anecdote … entirely fictional … not supported by historical evidence”), and Critchley (2010), who regarded the discovery as entirely Gideon’s. Dean (1998, 1999) described the details of the story as “specious” and attributed them to “poor scholarship”. He preferred a male-oriented version of events dominated by Gideon, in which his hero single-handedly discovered a dozen dinosaurs in a prolific career, outwitting the establishment’s elite experts and prevailing over adversity – a victimised character cast as a provincial amateur pitted against the professional anatomists and university dons.

More recent workers have sat on the fence on the issue, and regarded the find as Gideon’s “and/or” Mary’s (Lomax and Tamura, 2014), while a few still remain supportive of the “plausible” role played by the dutiful wife (for example, Benton, 1984 and Cadbury, 2001). The recent, well-received play Dinomania staged at the New Diorama Theatre in London, the final performance of which I saw in March 2019 (Fig. 7), brought more publicity to the life of the Mantells, and essentially followed the version of events as set out in Cadbury’s (2001) book.

Fig. 7. Cast of the play ‘Dinomania’, performed at the London New Diorama Theatre in 2019.

New evidence

It is important therefore to reproduce here the online post of Mr Andy Revell, who quotes an extract from a newspaper article that originally appeared in the Mid Sussex Times on Tuesday, 1 November 1887.

Revell quotes:

Mrs. Mantell, wife of Sir Gideon, then a surgeon at Lewes, being on a visit to her friend Mrs. Waller, wife of Mr. S.Waller, solicitor, of Cuckfield, the two ladies on walking over the green passed by a man by the roadside breaking lumps of stones; when Mrs. Mantell, perceiving what appeared to be a fossil on one of the stones, they stayed to examine it, and being satisfied of its nature gave the man a gratuity to take it to Mrs. Waller’s house, from whence Mrs. Mantell took it home for her husband’s inspection”.

Mr Revell concludes in his own words that: “Mantell named his discovery Iguanadon [sic] in 1825, becoming the first man to both discover and describe a species of what we know now as dinosaurs.”

However, further important and enlightening details are contained in the original newspaper article (see Fig. 8), a fuller version of which reads as follows:

…and passing by the cottage and over the stile I come into a pasture field in which is situated a modern and commodious farmyard, with every convenience attached, and a windmill for grinding corn and cutting chaff for the cattle and horses on the estate; and turning to the right pass the keeper’s house and along by the side of the old stonepits from which so many wonders of an Antidiluvian world have been exhumed, and wonder to myself what kind of a scene it presented when this spot was in the midst of an estuary, and, where the Iguanodon disported, and it was only a wide waste of waters peopled by gigantic reptiles. But coming out by Mill Hill on to Whiteman’s Green I have a tale to relate. Three quarters of a century since, or thereabouts, Mrs. Mantell, wife of Sir Gideon, then a surgeon at Lewes, being on a visit to her friend, Mrs. Waller, wife of Mr.S.Waller, solicitor, of Cuckfield, the two ladies on walking over the green passed a man by the roadside breaking a lump of stones, when Mrs.Mantell perceived what appeared to be a fossil on one of the stones, they stayed to examine it, and being satisfied of its nature gave the man a gratuity to take it to Mrs.Waller’s house, from whence Mrs. Mantell took it home for her husband’s inspection. Mr. Mantell having done so paid a visit to the pit and examined the rock the men were excavating, being told by them that often came upon what they called “curiosee” of that kind, and he was lucky enough to secure a few specimens, enjoining them to preserve what they happened to discover until his next visit, and he would remunerate them for doing so.

In consequence, they were careful in boarding up in the roundhouse of the windmill that stood in the grounds whatever fossils they came across, for which he handsomely paid them, until at length they discovered an immense bone, very much larger than any they had previously found, that they took great pains in preserving intact. This was consigned at once to Lewes, and pronounced to have been a rib bone of an immense reptile, or lizard, the Iguanodon, 80 feet in length and of corresponding height, of which other remains were shortly afterwards discovered. The old stone quarry has been filled up, the mill pulled down, and the ground levelled.

The quarrymen of that day are mostly gone the way of all flesh, and so has Sir [sic] Gideon Mantell, whose geological discoveries threw so much light on the pre-historic state of the world. But a visitor to Crystal Palace at Sydenham may find on the shore of the lake a full-sized facsimile figure of this gigantic reptile that probably thousands of years before man, or even any species of Mammalia, inhabited the earth, had been in existence. But no one can tell how, or on what, it existed, or the state of the globe at that time”.

Fig. 8. Original newspaper article from the Mid Sussex Times, 1 Nov 1887.

The author of this article is the ‘Saunterer’, who published various pseudonymous journalistic ‘saunterings’ for the newspaper, this being number VII. His/her identity is unknown to me at this time, so the reference is cited below as ‘Anon 1887’.

The significance

This reference has gone completely unnoticed for 133 years, but now serves to validate one of the most important anecdotes in the history of palaeontology. Thus, the tale of Mrs Mantell taking a stroll in Cuckfield and coming across one or more unusual fossil teeth in roadside rubble can finally be corroborated. It actually happened as largely supposed, the specimens soon after being handed over to Mary’s husband for his inspection. This throws cold water on the suggestions to the contrary made by the likes of Dean and Sarjeant, and negates MacGowan’s (2002) statement that events would “always be clouded in doubt”. Dean’s entire argument seems to value the lack of evidence for the story as evidence for the lack of a story, a dangerous position to adopt in any scientific research. Furthermore, there are important additional facts in the article that were previously unknown and which fill some gaps in our knowledge of the finds:

  • Mary was accompanied on her walk by her friend Mrs Bridget Waller, née Williams (1795-1867), who married Mr S Waller (a solicitor) in 1819.
  • Mary spotted the teeth in rocks being broken up by a workman, recognised them as being something unusual and of potential interest, and promptly acquired them.
  • Mary paid for the fossils, as her husband had also done on many occasions.
  • The date of this event must have been sometime between September 1819, when Mrs Waller got married and moved into her marital home of Leyton House (now Cuckfield House) in Cuckfield, and the summer of 1822, when Gideon published his seminal book The Fossils of the South Downs. Three quarters of a century (exactly) would give a retrospective date for the find of 1812, but the Saunterer was being approximate, the more likely period being sixty-odd years prior to 1887, and by my own reckoning probably 66 (see below).
  • The site of the discovery is given as the green at Whiteman’s Green near Cuckfield, not far from the Wallers’ residence. Gideon later visited the quarry and purchased material stored in the roundhouse of the windmill, and had material sent by post, details which corroborate the location of the quarry as Whiteman’s Green.

Analysis and conclusions

It is important to remember that this article was written nearly three quarters of a century after the event. Mantell was never knighted, as erroneously stated. Nevertheless, all the other details closely match those of the traditional story and confirm that Mary did indeed find the original wedge-shaped teeth at Cuckfield. There was even a witness to this, another woman, but it was evidently Mary who realised the potential significance of the fossils. Gideon may well have had other, unworn Iguanodon teeth before this discovery according to Dean (1999), possibly acquired from quarry workers, but none resembling Mary’s finds has been documented.

As for the date of the discovery, in his blog, Mr Revell quotes the year 1822, as do many other researchers, but there is no direct evidence for this. Cadbury (2001) suggests 1820 or 1821. Three quarters of a century or thereabouts is, unfortunately, an imprecise timescale from our Saunterer. We know that Mrs Waller was married in September 1819 and moved into a house in Cuckfield with her husband, so Mary’s visit must have been after this date. Nothing is mentioned specifically in Gideon’s journal, extracts of which were published by Curwen (1940), that might offer verification to conclusively settle the matter.

However, another important aspect of the original story is that Gideon himself was not present, as borne out by this new article, but was visiting a patient. Intriguingly, there is a journal entry that might just offer a possible alternative option for the date of the walk, and which also coincides with a visit the Mantells made to the vicinity of Cuckfield. On 21 May 1821, Gideon records in his journal that, after a “laborious morning”, he drove his wife to a Mr Egles of Fletching (near Uckfield, see. Fig. 4) to see her cousin Mrs Tilney, arriving there at 3 o’clock. He then went on alone to visit the Earl of Sheffield, Mr Holroyd, at his residence of Sheffield Park. Gideon recounted that “we” (that is, he and his wife) later walked in the grounds and returned to their home in Lewes that evening, arriving at 9pm.

The next day, on 22 May, Gideon wrote the following note in his journal, which may prove to be of relevance: “some interesting specimens brought me from Cuckfield”. In other words, these fossils were not received by post like other consignments from the Cuckfield quarries, but were evidently delivered by hand. Although not conclusive on this point, it is certainly possible that, during the day on 21 May 1821, Mary may have visited her friend Mrs Waller in Cuckfield, only 8 miles from Fletching, while her husband visited the Earl in the afternoon.

Gideon does not stipulate whether his visit to the Earl was for professional or social reasons, but, in any case, the original anecdote of him visiting a patient seems to be consistent with this particular appointment. Presumably then, it was Mary who brought the fossils to Gideon personally the following day, 22 May, but further research is needed to shed more light on the matter. Gideon’s note that these particular Cuckfield specimens were “interesting” is important because there are no other specific references to the discovery of any unusual fossils made by either Mary or Gideon between 1819 and the often-quoted date of 1822. This is curious in view of the importance he later attached to the discovery of Iguanodon.

According to the newspaper report, Mary realised that the fossils were unusual and paid the worker a gratuity, the first evidence we have that she bought fossils from workmen just as Gideon had done habitually to build up a collection. This is more proof that his wife was actively contributing to a partnership focussed on acquiring valuable research specimens of local Cretaceous fossils.

As such, her input to the couple’s studies involved not only personal collecting, but also acquiring material indirectly from third parties. It is well known that Mary provided many of the illustrations for some of her husband’s early books and, despite Gideon’s reservations, her drawings are of high quality (Fig. 9). She also wrote at least one scientific article in her own right (Mantell, 1818), a fact not widely publicised. The breakdown of the Mantells’ marriage is well documented, although the couple technically separated and Gideon thereafter provided financially for Mary. A divorce would have required an act of parliament.

Fig. 9. Head of the famous Ichthyosaurus (Temnodontosaurus platyodon) found by Joseph Anning, as copied by Mary Ann Mantell from the plate in Home’s original paper. Author’s collection, previously unpublished.

After numerous periods apart, Mary finally left for good in 1839 to live near Exeter with the family housekeeper, Hannah Brooks, staying there until her death in 1869. Somewhat cruelly perhaps, Gideon instructed his son Walter to delete any journal entries referring to his wife on the event of his death (1852), and there is no doubt that he was bitter about the breakup of his marriage for the rest of his life.

Gideon endured prolonged bouts of depression and admitted he had not found the “path of peace” (Curwen 1940, p.128). He probably suffered from bipolar disorder and was evidently obsessed with enhancing his own reputation. Sadly, in doing so, his personal life suffered. As Curwen (1940, p.vi) so eloquently put it: “his ambition was not so much to serve mankind as to make himself a name, a form of selfishness which can bring no true satisfaction”.

Gideon could be unreliable in recording his fossil discoveries and his accounts are sometimes inaccurate. Towards the end of his life, he even claimed to have found the Iguanodon teeth himself (Mantell 1851), but this of course was after the relationship had failed and he was, in his own words, “downright savage in mind” (Curwen 1940, p.14). There are numerous other instances where he did not properly acknowledge the actual finder of the fossils in his collection. For example, the fossil plant ‘Clathraria’ (a cycadeoid), which he claimed to have picked up on a beach on the Isle of Wight (Mantell 1854, p.214), was in fact purchased from a local labourer (Curwen 1940, p.193).

Regardless of any resentment or animosity arising from the separation, it is unfair that Mary has not received due credit for her palaeontological contributions. Descriptions of the story as charming or fanciful made by (mostly) male writers, although somewhat patronising, must be seen in the context of geology traditionally being a male-dominated science.

That it was a woman who made such a significant palaeontological discovery in Regency England is remarkable considering its patriarchal society, her contribution ranking alongside those made by other exceptional contemporary females such as Mary Anning of Dorset or Etheldred Benett of Wiltshire. In my opinion, the most important thing is not that the teeth fell into Gideon’s hands (Norman 1985), but that the true version of events is well documented and Mary receives the credit she deserves. Only now is a species being named in her honour, an Early Cretaceous insect preserved in amber (Jarzembowski, in prep).

Mary’s involvement in the story of the discovery of Iguanodon may well have been gradually written out of history, had it not been for Mr Revell’s chance rediscovery of this article from the Mid Sussex Times of 1887, a “Revellation” indeed. Other, fascinating new data on the Iguanodon story have recently been unearthed (Simpson, 2015) and hopefully more will be forthcoming with further research.


I thank Dr Alistair Ruffell for his critical review of the original manuscript. The photograph in Fig. 2b is reproduced with kind permission of the Alexander Turnbull Library, New Zealand.

About the author

Martin Ian Simpson (b 1958) is a freelance palaeontologist living on the Isle of Wight. His research is focussed on Mesozoic lobsters, Isle of Wight geology and the history of fossil collecting in the UK. He has described numerous new species of fossil lobsters and a small pterosaur from the Lower Greensand.

Further reading

Dinosaurs of the British Isles, by Dean R Lomax and Nobumichi Tamura, Siri Scientific Press, Manchester (2014), 414 pages (softback), ISBN: 978-0-9574530-5-0


Anon. 1992 Dinosaurs! Discover the past of the Pre-historic World (magazine). Issue 1, p20-21. Orbis, London.

Anon 1887. Mid Sussex Times Nov 1. Saunterings by a Saunterer no VII.

Benton M 1984. Pocket Dinosaurs. Kingfisher, London.

Cadbury D 2001. The Dinosaur Hunters. A story of scientific rivalry and the discovery of the pre-historic world. Harper Collins, London.

Colbert EH 1971. Men and Dinosaurs. The search in field and laboratory. Penguin, England.

Critchley E 2010. Dinosaur Doctor. The life and work of Gideon Mantell. Amberley, Stroud.

Curwen EC 1940. The journal of Gideon Mantell surgeon and geologist covering the years 1818-1852. OUP.

Dean DR 1998. Gideon Algernon Mantell. A bibliography with supplementary essays. New York.

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Lomax DR and Tamura N 2014. Dinosaurs of the British Isles. Siri Scientific Press, Manchester.

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Mantell GA 1854. Geological excursions round the Isle of Wight, and along the adjacent coast of Dorsetshire. 3rd edition, Bohn, London.

Mantell MA 1818 Description of a Roman vase found at Dorchester. Provincial Magazine (Lewes) 1, p57-58.

Norman D 1985. The illustrated encyclopaedia of dinosaurs. Salamander, London.

Sarjeant WAS. 1997. The earliest discoveries. In Farlow JO and Brett-Surman MK. Eds. The Complete Dinosaur. IUP. (2nd edition 2012, rewritten by Spalding DAE and Sarjeant WAS).

Simpson MI 2015. Iguanodon is older than you think: the public and private announcements of Gideon Mantell’s giant prehistoric herbivorous reptile. Deposits 44, p33.

Spokes S 1927. Gideon Algernon Mantell, LLD, FRCS, FRS, surgeon and geologist. Bale, sons and Danielson, London.

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