Examination of sandstones in Britain in a study of the relation of their clay mineral content to soil formation has resulted in data of geologic interest. Dickite and kaolinite have been found in Carboniferous and middle Jurassic beds. The detection and separation of the clays, their form and mode of occurrence, and associated light and heavy minerals are described. A report on the differentiation of dickite and kaolinite, by George Brown, is appended.