In 1938–39 the D'Arcy Exploration Company, Limited, sank a borehole (Eskdale well no. 2) to a depth of 5040 feet near Aislaby, Eskdale, Yorkshire, to test the oil or gas possibilities in the Permian Magnesian Limestone. As the well was some distance from any previous boring through the Permian salt series, the Company undertook to carry out continuous coring through this series in the public interest. The boring passed through Lias, Rhaetic, and Trias, and finished in the Permian Lower Magnesian Limestone. The geological results of this boring have been discussed by Lees and Taitt (1945), and fig. 1 has been reproduced from their paper. It can be seen that three evaporite beds were passed through; two in the Upper Permian salt zone, and one in the Middle Permian.