Too Big to Walk. Brian J. Ford

had been unearthed, and had wrongly assumed that it belonged on the snout (like the horn on a rhinoceros). He drew attention to the creature’s huge hindlegs, which he compared with those of an elephant, and concluded that their bulk was necessary to fit it for a life on land, writing that ‘the legs must have sustained the weight of the body in a manner more nearly resembling those in the pachydermal Mammalia.’

      Gideon Mantell illustrated his 1825 paper for the Royal Society with this plate showing the Tilgate Forest iguanadon teeth in comparison with the jaw of an existing iguana. The genus of his fossil has since been reclassified as Therosaurus.

      On October 26, 1825, Mantell sent a package of his specimens to Professor Adam Sedgwick at Cambridge University, including ‘casts of the best teeth of the Iguanodon in my collection’ – the originals he kept for himself. Mantell was writing up his notes for a new book on the geology of Sussex and this was to be a landmark publication. Mantell usually referred to it by part of its subtitle: ‘the fossils of the Tilgate Forest’. The specimens were illustrated by his wife Mary Ann in exquisite detail, and have a photographic clarity. For the first time Mantell described the fossil reptiles in detail – the contents page listed them: Crocodiles, Megalosaurus, Iguanodon, Plesiosaurus … these giants of prehistory were now becoming familiar to the academic world. Dinosaurs had at last arrived on the scientific scene.42

      The book proved to be a landmark, and its level of detail is astonishing. Mantell discusses with precision the strata in which the fossils were found, dissecting each layer meticulously, so that the book stands today as a definitive statement. This is no amateurish essay into the unknown, but a serious scientific study. Yet the workload was almost unendurable: in his dedication of the book to Davies Gilbert, the Member of Parliament for Bodmin in Cornwall, Mantell wrote: ‘You are fully aware of the disadvantages under which I have laboured, and will generously make every allowance for the imperfections of a work, composed amidst engagements of the most harassing nature.’ Yet he pressed on, and in 1832 discovered the third dinosaur to be scientifically described. It was only half the size of the Iguanodon and Megalosaurus, measuring less than 30 feet (9 metres) long. It was found, again, in strata at Tilgate Forest, and Mantell wrote: ‘I venture to suggest the propriety of referring it to a new genus of saurian … and I propose to distinguish it by the name of Hylæosaurus.’ In spite of his continued success, life was not easy; in 1833 Mantell moved to the seaside resort town of Brighton but could not sustain his medical practice, and, when he became impoverished, his home was converted by the town council into a museum.

      The following year, Mantell received some dramatic news: Iguanodon fossils had suddenly been found in a quarry near Maidstone, in Kent. He decided to investigate, but by the time he was able to reach the site, the strata had already been blown up with gunpowder (the standard accounts all say that the rocks were ‘dynamited’ but that explosive was not invented for another 30 years). Just one fossil-bearing slab survived the demands of the quarrymen, and the owner demanded £25 (in 2018 about £1,200 or some $1,600) before he would release it. Mantell didn’t have any spare money, but a group of his friends clubbed together to purchase the rock. It was transported to his home, where it took pride of place in his personal museum. With typical British wit, they called it the Mantell-piece. It proved impossible to separate out the individual bones, so Mantell and his wife worked on reconstructing the appearance of the remains from what they could see. The rock, formally named the Maidstone Slab, can be seen to this day hanging lost and lonely in the dinosaur gallery at the Natural History Museum in London. That is not the new dinosaur gallery; if you follow the signs, you will come to a kind of indoor theme park illustrated with inane cartoons and littered with shops selling plastic souvenirs, fridge magnets and children’s clothing. The new dinosaur display in that museum is like a gloomy version of Disney World, and most of the Victorian specimens are hanging on a high wall in a nearby gallery where few people notice them.

      Mantell’s reconstructions of the dinosaur are largely based on this specimen, and he construed it as a quadruped with the proportions of a bear. Mantell made a sketch on paper which showed the bones they could recognize, placing the horn on the nose; and this remained the conventional interpretation for a century. Mantell began to give public lectures on his work at his home museum, and they proved so popular that in 1838 they were published in a single book devoted to the wonders of geology.43

      Mantell so liked showing visitors around the collections that he frequently overlooked charging the standard entrance fee, and the museum soon became insolvent. By now he was becoming desperate, so he offered to sell his entire collection to the British Museum for £5,000 and readily accepted their counter-offer of £4,000 (worth some 50 times as much today: about £200,000 or $250,000). Mantell, who had become the founding father of dinosaurs after his wife’s prescient discovery of that first Iguanodon tooth, cut back on his fossil lectures and moved to Clapham Common in London to concentrate on practising as a physician. In 1839 Mary Ann left Gideon and emigrated to New Zealand, later sending him some new fossil discoveries, while their daughter Hannah died in 1840. The next year saw a dreadful accident: Mantell was caught in the reins of his horse-drawn carriage and severely damaged his back. From that day onwards his spine was painful and problematic. He moved to Pimlico in 1844 and, confined largely to his home, he continued to write books and papers on his discoveries, deadening the constant pain with laudanum, the solution of opium also taken by Mary Anning.

      A horn had been found by Mary Mantell among the fossilized iguanodon remains, and when her husband sketched how the animal might have appeared in life, he placed it on the snout. Copies of this incorrect view still appeared 138 years later.

      Mantell was the world’s first authority on dinosaurs; four of the five dinosaurs then known had been discovered by him and his wife. Although his life had been enriched with so many discoveries, after his wife left him and he suffered his fall, the pain became increasingly severe. Eventually, on November 10, 1852, Mantell over-dosed on the laudanum, and he died that same afternoon. He was 62. Opinions are divided as to whether it was an accidental overdose or suicide. At autopsy, it was discovered that his vertebral column had curved, a condition now known as scoliosis.44 After the post-mortem dissection, a section of his spine was removed and preserved for study, and it remained in the pathology museum collection of the Royal College of Surgeons of England until 1969 when it was unceremoniously thrown away, due to a lack of storage space. In 2000, to commemorate Mantell’s discovery, a monument was unveiled at Whiteman’s Green, Cuckfield, where Mary Ann had found that first tooth. Maidstone, where the celebrated ‘Mantell-piece’ slab had been retrieved, adopted the iguanodon on its coat of arms. On the town’s crest, a lion supports a shield on the right, with an iguanodon on the left. The official designation is written in the ancient blend of Norman French and English beloved of heraldry specialists:

      Arms: Or a Fesse wavy Azure between three Torteaux on a Chief Gules a Lion passant guardant Or.

      Crest: Issuant from a Mural Crown Or a Horse’s Head Argent gorged with a Chaplet of Hops fructed proper, Mantled Azure doubled Or.

      Supporters: On the dexter side an Iguanodon proper collared Gules and on the sinister side a Lion Or collared Gules.

      Motto: AGRICULTURE AND COMMERCE.

      In the Maidstone Museum, there is a stained-glass window with the iguanodon on display. Neither the published version of the iguanodon, nor the one in that window, has that horn on the snout.

      Maidstone, close to where the Mantells made their discoveries, was granted a coat of arms in 1619. In 1949 the two supporters either side were added, a collared lion (on the right) and an Iguanodon. This version shows the correct snout.

      By this time, new fossil dinosaurs were being discovered in France. Remains of a large creature were described in 1838 by a French palæontologist, Jacques Amand Eudes-Deslongchamps, who lived in Normandy. He didn’t have