Thick evaporites are present in the Permian beneath the North Sea, and can be correlated with the known successions in Germany and in England. The evaporites are more widespread in the upper division (Zechstein) than in the lower (Rotliegendes). This paper deals chiefly with the Zechstein of the English side of the basin, in which four main evaporite cycles are present.

Zechstein salt movement commenced near the end of the Early Triassic when the overburden was only about 2,000 ft, and continued throughout the Mesozoic and Tertiary. Movement was earlier in the west than in the east. Salt plugs are associated particularly with the margins of a large NNW-SSE-trending trough which became fully developed during the Jurassic.

Important structural features and thickness changes in the Mesozoic and Tertiary rocks originated as a result of the salt movement, and are compensated almost entirely by salt at depth. As a result, the base of the Permian nearly is parallel, on a regional scale, with the base of the Quaternary though separated from it by about 10,000 ft of moderately complicated strata.

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