The Carbonaceous or Black Shale or Richmond Formation of Jamaica is a deposit of considerable importance in connexion with the geological history of the Greater Antilles. R. T. Hill1 correlates provisionally the Richmond Formation, as he calls these beds, with the Scotland Series of Barbados, the oldest formation in that island, and also with certain of the Tertiary beds of Trinidad. In the present communication I shall endeavour to present some observations on the Carbonaceous Shale Series of Jamaica, together with a description of the fossils I collected in it. This series of deposits consists of a sequence of ferruginous sandstones both coarse and fine-grained, some of them very hard, others when weathered extremely friable; of impure carbonaceous limestones of a very unfossiliferous nature; of grey nodular friable shales often with carbonaceous plant-like remains in them, but scarcely any other fossils; and of coarse conglomerates which seem to occur chiefly in the lower part of the formation.