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Excerpt from Geology of the British Isles The completeness of the geological record in the British Isles, the variations in the facies of the different formations from place to place, and the immense volume of the literature that has accumulated, render it impossible for one man to do justice to the Regional Geology of the area. It was therefore decided to divide the work among a number of specialists, each of whom could write with authority on the subject allotted to him and be individually responsible for his contributions. Every effort has, however, been made to secure as much uniformity as was possible in bibliographical and typographical details. The majority of the illustrations have been taken by permission from the official Reports of the Geological Surveys and the publications of the Geological Society and of the Geologists Association, the exact source being given in each case. The general maps have been prepared by A. Morley Davies, who has made a careful study of the structural geology of the whole country. He also had the advantage of detailed information supplied to him by other contributors. I am however responsible for the symbols employed on the structural maps, and the system of shading adopted in those showing the distribution of the different formations at the surface. Other maps and diagrams have been specially prepared for the present work by the contributors, who are identified by their initials. The folds and faults of England and Wales are usually grouped in four systems, according to their general axial directions: 1. The Charnian system, with N.W. - S.E. direction; 2. The Caledonian system, with N.E. - S.W. direction; 3. The Malvernian system, with N. - S. direction; 4. The Armerican system, with direction varying from E.N.E. - W.S.W. through E. - W. to W.N.W. - E.S.E. To each of these systems an age of predominance may be assigned, but the use of any name must not be taken as implyin