In December 1912, Arthur Smith Woodward, keeper of palaeontology at the Natural History Museum, and Charles Dawson, an amateur geologist, delivered a sensational paper to the Geological Society in London announcing the discovery of a primitive ape-like ancestor of Man at Piltdown, Sussex. 'Piltdown Man' was welcomed as evidence of the 'missing link' between apes and humanoids.
Dawson had unearthed part of a skull and jawbone along with primitive tools during a dig in a gravel pit at Piltdown. The finds were significant because the skull fragments were 'humanoid' in nature, while the jawbone was distinctly ape-like, apart from its teeth which were human-like. This fitted in with the prevailing view of humanoid development that the first 'human' feature to develop was the enlarged brain. Further finds at the site, including tools, appeared to confirm the view that Man's earliest ancestor had been discovered. Smith became involved in the episode as he was considered as the leading expert of the comparative anatomy of the brain. Smith having examined an endocranial cast reconstructed from the finds, and declared them to be evidence of the most primitive ape-like brain yet discovered. Other experts rejected this thesis from the start, but some of the most damaging criticism were made by Arthur Keith (1866-1955), Conservator of the Hunterian Museum of the Royal College of Surgeons, who was concerned about the reconstruction of the vault bones of the skull. In February 1914, Smith read a paper on Piltdown Man to the Royal Society, which was based on the original reconstruction of the skull. Keith, who was in the audience, challenged Smith's findings and a heated argument ensued. Eventually, however, Keith came to accept the integrity of the findings, following further excavations at Piltdown, including the discovery of a second individual in 1915 (later extensive excavations at the site were to reveal no more fossil remains).
For many years Woodward's view that a new creature had been discovered was accepted by all but a few sceptics. However, subsequent research was to challenge the view that humanoid creatures from the Pliocene era could have had large brains. In the 1950s Piltdown Man was exposed as a fraud following chemical analyses of the bones. These revealed the skull came from a modern human and the jawbone from an orang-utan. The bones were found to have been stained and abraded to give an appearance of great antiquity. The ultimate perpetrator of the hoax remains unknown; Charles Dawson as the discoverer of the bones was considered an obvious culprit, but it has also been suggested that Martin Hinton, a junior of Smith Woodward's at the Natural History Museum, played a leading role in the affair.