The accompanying figure gives a clear idea of the sequence of beds drawn from a photograph which we owe to the kindness of the Abbé Bonno.

These gravel quarries are excavated in the Pleistocene or Quaternary gravels and are situated on a plain between 125 and 140 feet in height

The Beds at Chelles, containing Prehistoric Flints, Etc.

above the sea, extending from Chelles eastward to the neighboring village of Brou. The strata underlying the fresh water or river-gravels are greenish clays or marls of marine origin and of Eocene Tertiary age. This marl contains gypsum or plaster of Paris, with crystals of