It is now fifteen years since the appearance of the second edition of the late Professor Jukes's memoir on the Geology of the South Staffordshire Coal-field. The author observed in his preface that a revision of his work had been rendered necessary by the opening of many new mines and cuttings of various kinds which had afforded fresh information on points that had previously been obscure. He mentioned, for instance, certain red clays and sandstones occurring at Walsall Wood, and at other places which were at first supposed to belong to the New Red Sandstone, afterwards believed to be Permian, but were ultimately decided to be Coal-measures.