The Chloritic Marl in the Wealden district furnishes much phosphatic material, which has been extensively worked at Froyle.
Phosphatic nodules occur also in the Chloritic Marl of the Isle of Wight and Dorsetshire, and at Wroughton, near Swindon.
To N.E.; this is succeeded by a belt of gabbro, and finally the eastern border is again occupied by micaceous and chloritic schists.
The green colour is due to a chloritic mineral; the red to haematite.
In the Black River Mountains, at a height of about 1200 ft., there is a clay-slate; and near Midlands, in the Grand Port group of mountains, a chloritic schist occurs about 1700 ft.