The chalk ball

The ball, illustrated in Revue Archéologique 5

In August 1861, miners excavating Eocene lignite at Montaigu, near Laon (France) discovered a chalk ball about 60 mm in diameter and weighing around 310 g at a depth of about 75 m; it rolled for some distance from a block detached from the passage. Thinking it unusual, they reported it to a local Dr Lejeune who in turn gave it to Maximilien Melleville (1807-1872), the Vice President of the Société Academique de Laon (France) and author of Dictionnaire historique du département de l’Aisne (1857). He published an account in Note sur les silex taillés des départements de la Somme et d l’Aisne, in which two photographs of the ball were reproduced, and later gave a fuller description in Revue Archéologique 5, 181- 186. A translation of Melleville’s report appeared in The Geologist of April 1862. The conventional date for the lignite beds in which it was found is 45 to 55 million years old. He was in no doubt that the ball was genuine, as it had been stained a black colour by contact with the lignite except for a small circle at the top, where it had protruded through into a shaly deposit above, which retained the pale yellow of natural chalk.

This discovery seems perfectly genuine, but it is unclear why anyone believed that the ball must have been the product of human manufacture. Moreover, the published photograph does not give any confidence in Melville’s description, showing instead a roughly spherical object with unevenly stained surfaces. Melville provided no evidence for the object having been carved, but insisted that if it had been formed by wave action on an Eocene beach, it would ultimately have dissolved. However, it is much less accurate a sphere than a simple description would suggest: the illustrations certainly depict a very rough ball that looks as if it could easily have formed through natural weathering processes.