The Permian in Durham, northeast England, at depth is a dark, dolomitic rock with an abundance of sulfates and chlorides; at the surface, it consists of sands, marls, and a magnesian limestone. Evidence of thrusting and other movements occurs widely, and it is described at various localities in the vicinity of Sunderland. The Permian and overlying strata were lowered by downwarping and then, during differential uplift and denudation, the salts were removed by percolating sea water. Displacements and thrusting which occurred may have been the result of a decrease in volume following solution.

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