The type section of the Speeton clay of lower Cretaceous age, at Speeton, on the Yorkshire coast, northern England, is 300 feet thick and is the equivalent of the thousands of feet of marls and limestones in southeastern France. Although non-sequences occur, beds of all six lower Cretaceous stages are known to occur. A detailed lithologic column is given, with faunal zones. Depositional and paleogeographic conditions are described. Slow accumulation is postulated, with prolific development of a benthonic fauna and, instead of a reducing environment, simply a lack of oxidation. The most likely source of detrital material was probably Jurassic beds to the southwest, which would account for the abundant iron and the mica in some horizons.