Attention has lately been called by M. Marcellin Boule to the production in cement-mills in the Commune of Guerville, near Mantes, of all the more characteristic forms of Eoliths, and of these he has given photographic reproductions. The evidence for the necessarily artificial shaping of Eoliths had for many years been questioned by him, because he had found chipped flints of this character in the midst of Oligocene or Miocene beds in Auvergne and in the Velay; and it seemed imprudent to infer the existence of man in those early stages of the Tertiary period in the absence of osteological evidence.