1. The Speeton Clay of Yorkshire contains abundant Foraminifera in the beds named by Mr. Lamplugh B (base), C10, and C2; but the specimens examined from the other subdivisions of F, E, D, and C either do not contain any Foraminifera or they are present in small numbers only.

2. Two new species, Cristellaria chapmani, Pulvinulina lamplughi, and a new variety, Lagena apiculata, var. danfordi, occur and are described. Forty-four species belonging to sixteen genera have been found.

3. The characteristic of the Foraminiferal fauna of the Speeton Clay is the great predominance of Pulvinulina caracolla (Roemer) over all other species.

4. Twenty-five per cent of the species of Foraminifera occur also in the Hils of North Germany, 35 per cent in the Red Chalk of Speeton, 40 per cent in the Bargate Beds of Surrey, and 58·5 per cent in the Gault of Folkestone.

5. Dimorphism is clearly shown by P. caracolla (Roemer). Previously it has been stated to occur among the Pulvinulinæ in P. partschiana, d'Orb., but no case has been described.

6. Notes are given on the microscopical characters of the sediments.