An eolith (from Greek "eos", dawn, and "lithos", stone) is a chipped flint nodule. Eoliths were once thought to have been artifacts, the earliest stone tools, but are now believed to be naturally produced by geological processes such as glaciation.
The first eoliths were collected in Kent by Benjamin Harrison, an amateur naturalist and archaeologist, in 1885 (though the name "eolith" wasn't coined until 1892, by J. Allen Browne). Harrison's discoveries were published by Sir Joseph Prestwich in 1891, and eoliths were generally accepted to have been crudely made tools, dating from the Pliocene. Further discoveries of eoliths in the early 20th century – in East Anglia by J. Reid Moir and in continental Europe by Aimé Louis Rutot and H. Klaatsch – were taken to be evidence of human habitation of those areas before the oldest known fossils. Indeed, the English finds helped to secure acceptance of the hoax remains of Piltdown man.
Because eoliths were so crude, concern began to be raised that they were indistinguishable from the natural processes of erosion. Marcellin Boule, a French archaeologist, published an argument against the artifactual status of eoliths in 1905, and Samuel Hazzledine Warren provided confirmation of Boule's view after carrying out experiments on flints.
Although the debate continued for about three decades, more and more evidence was discovered that suggested a purely natural origin for eoliths. This, together with the discovery of genuine early Lower Pleistocene Oldowan tools in East Africa, made support for the artifact theory difficult to sustain.