Page:Early Man in Britain and His Place in the Tertiary Period.djvu/43

other forms intermediate between the marsupials and the true placental mammals.

Fig. 2.
Nummulites lævigata. Bracklesham, 1/1. The Eocene strata^[1] are found in the area to the south-east of a line passing from the Wash to Charmouth in Dorsetshire, and are mainly centered in two basins, named, respectively, that of London, and that of Hampshire and the Isle of Wight. They occur over a very wide area on the continent. They are divided into three groups, the lower or Pre-nummulitic, the middle or the Nummulitic, and the upper or the Post-nummulitic, the widely spread foraminifer, Nummulites (Fig. 2), offering a ready means of determination of age, not merely in Europe, but throughout Asia, and a large part of Africa. The following table represents the thickness, characters, and conditions of deposit of each of the subdivisions in England, together with their equivalents in France, as determined by the recent researches of Professor Gaudry.

1. For a systematic account of the Eocene strata, see Lyell, Student's Elements, c. xvi.