Concealed with this buried tropical forest were the remains of aquatic invertebrates. From his early studies on the Downs, Gideon Mantell was an expert on the marine invertebrates of the chalk deposits. The invertebrates of the Weald were different. He could not see the familiar whorls of the ammonite or snake-stone, of belemnites, nautilus or other shelled creatures which once swarmed in the primitive seas that formed the chalk. Instead there were the casts of shells that he did not recognise; impressions sometimes so faint that they left just the barest trace of their external forms: the hinge of two joined shells, as in certain types of clam and pearl mussel, or the fragmentary pieces of a species of snail, perhaps. It was indeed tantalising; fragments both familiar and unfamiliar, never quite forming a complete fossil or displaying a clear marking. Uncertain what they could be, Mantell wrote to his usual correspondents such as James Sowerby, an expert on fossil shells, hoping he would shed more light on these invertebrates.
As for the massive animal bones that were scattered among the debris of this tropical forest, they remained indecipherable; an ancient hieroglyphic for which he did not have the code. He was increasingly certain that many of the bones, such as the giant thigh bone, did not match those of the sea lizards. They were far too chunky and solid. Although some of the bones were rather like those of ancient crocodiles, he had two sets of very large teeth that were not: the worn teeth of a herbivore and the blade-like teeth of a carnivore. ‘Of the numerous specimens in my collection not one is perfect; by far the greater part consisting of fragments rounded by the action of water and deprived of the anatomical distinctions so necessary to the elucidation of the form of the original,’ he wrote, utterly baffled by these remnants of a ‘former creation’.
His investigations were becoming so compelling that other aspects of his life paled by comparison. ‘Murdered two evenings at cards,’ he complained in his diary. Whether attending the local sheep fair or the ever-popular Brighton races, as a doctor he had a position to maintain in the heart of the community. In provincial society it wouldn’t do to appear hurried, or unavailable. But each night when his duties were done he would pore over the details of the animal bones and tropical vegetation, trying to make sense of the wild profusion of relics from this ancient time.
On the evening of 4 October 1821, an unexpected visitor arrived at Castle Place who was able to help him. Mantell was summoned downstairs to meet a young man who ‘presents nothing remarkable, except a broad expanse of forehead,’ he wrote. ‘He is of the middle size … small eyes, fine chin and a rather reserved expression of countenance.’ The stranger introduced himself as Charles Lyell. Lyell had been visiting his former school in Midhurst, Sussex, when quarrymen had told him of a ‘monstrous clever mon, as lived in Lewes … who got curiosities out of the chalk-pits to make physic with’. The quarrymen were Mantell’s labourers, and Lyell was so intrigued by their account that he rode for twenty-five miles across the Downs to track the man down.
It was soon apparent that Lyell and Mantell had a great deal in common. ‘Mr Lyell is enthusiastically devoted to geology,’ Mantell entered in his diary; ‘he drank tea with us and we sat chatting on geological matters till now – midnight’. Lyell’s interest in geology had started while at Oxford University. Although studying classics, he had been drawn to Buckland’s inaugural lectures in which the professor was at his most electrifying. Lyell’s father had written to a friend, ‘Buckland’s lectures are engaging [my son] heart and soul at present.’ Afterwards, in keeping with his position as the eldest son of minor gentry, Lyell had embarked on a career in law in London, but his eyes gave him trouble. Eventually, his father had indulged his interest in science and taken him to Europe. During one carriage tour across the Alps, Lyell had studied the effects of glaciers on the landscape; on a second trip, he had observed the effect of rivers in forming a coastal plain on the Adriatic coast of Italy.
Since his family was wealthy, with a large estate in Scotland, Lyell had an independent income and more leisure for geology than Mantell. The following day, while Mantell was visiting patients, he went to explore the Sussex strata and then returned to Castle Place: ‘to have tea at six o’clock,’ Mantell wrote. ‘My few drawers of fossils were soon looked over, but we were in gossip until morning.’ The visit marked the beginning of an enduring friendship between these two men, both hoping to make a career from geology.
Although there is no record of their conversation over these two days, there is evidence that Lyell told Mantell of Buckland’s giant reptile in the Ashmolean Museum and they compared the Stonesfield fossils in Oxfordshire with those of Cuckfield in Sussex. Fired by these discussions, soon after leaving, Lyell lost no time in visiting Stonesfield to obtain a boxful of fossils that he despatched to the Lewes wagon office. Three weeks later, on 25 October 1821, Mantell wrote in his diary: ‘received an interesting collection of Stonesfield fossils from Mr Lyell; in many respects they resemble those of Cuckfield’.
Charles Lyell’s news of the huge reptilian bones in Oxford confirmed for Mantell that his fossils were not just of provincial interest. He learned not only that Georges Cuvier had concluded that the Stonesfield beast was a reptile, but also that it was at least forty feet long and as bulky as an elephant. Armed with this information, Mantell felt that his own speculations of giant lizards buried in the Weald did not seem quite so preposterous. He could now attempt to classify his own fossils by seeing which bore most resemblance to the giant Oxford lizard.
About this time, Mantell almost certainly heard from Lyell of William Buckland’s intention to publish a detailed paper on the Stonesfield reptile. Since Buckland, the famous Regis Professor, was planning to describe and name the new carnivorous lizard, it was hardly appropriate for the unknown Mantell to claim this opportunity for himself. However, no one had reported anything like the unidentified herbivorous teeth. Mantell felt, therefore, that he could be the first to identify this animal, new to science, and claim the recognition, without interfering in Buckland’s study.
Patiently taking advantage of any introduction he could negotiate, Gideon Mantell sent a prospectus of his planned book on the geology of Sussex to members of the landed gentry, inviting them to subscribe for copies. The Earl of Chichester, the Bishop of Durham, the Earl of Egremont and numerous others replied; in all he attracted two hundred subscribers. Better still, in 1821 an envelope arrived from Carlton House Palace. Mantell broke the royal seal, and read: ‘His Majesty is pleased to command that his name should be placed at the head of the subscription list for four copies.’ Quite how George IV had heard of the book is unclear; Mantell wrote back simply, ‘I am indebted to J. Martin Cripps Esquire for this honour.’ But there can be no doubt of Mantell’s response: the royal encouragement was, he said, ‘most gratifying to my feelings’. He had great expectations now that his book would place him ‘in the first circles’ and allow him some means of devoting more time to geology. The carelessly rich could so easily liberate him from his unrelenting daily round of chores.
Fossils of the South Downs, published in May 1822, reveals the progress Gideon Mantell had made in interpreting the strange fossils buried in the Weald. In the preface he pointed out ‘that his labours were snatched from hours of repose … a record made under circumstances unfavourable to literary pursuits’, and he even apologised for the quality of his wife’s drawings. ‘As the engravings are the first performances of a lady but little skilled in the art, I am most anxious to claim for them every indulgence … although they may be destitute of that neatness and uniformity which distinguish the works of the professed artist, they will not, I trust be found deficient in the more essential requisite of correctness.’
Gideon Mantell began by classifying the strata of Sussex. The lowermost and oldest Secondary rock he identified as the ‘Iron Sand’. Above this in order of succession he placed the limestone, sandstone and slate where he had found the giant bones, calling this the ‘Tilgate Beds’ named after the Tilgate Forest. This was followed by Weald clay, greensand and several chalk formations. On top of these Secondary layers came the more recent