This thesis attempts within a more limited area, and by a more exhaustive analysis than is usual, a phytosociological investigation of some relic woodlands in the North of England. In and around the woodlands some 226 Aufnahmen were made and nine Associations recognised. A further six partial Associations or noda are considered. Epiphytic communities are studied in detail in some 257 Aufnahmen and a number of epilithic communities also are examined. From these, ten epiphytic Associations or parts of Associations are described and a number of epilithic Associations indicated. The Associations of the ground flora are related to the system advanced by Lohmeyer et al (1962) and emended by Westhoff and Den Held (1969), and some phytogeographic relationships of the kindred Alliances are considered. The epiphytic Associations are fitted as far as possible into the framework advocated by Barkman (1958) and some relationships are noted between the epilithic Associations and those of Klement (1955)'The thesis is divided into six parts:-Part I reviews the previous work done in the area; introduces the problems of application of phytosociological methods within a restricted area; and outlines the geology, topography, climate, and other factors, as they bear on the ecology of that area. Part II summarises the history of woodland vegetation in the North of England; examines the general structure and composition of the woods in question; and considers them from a general ecological stand point as they compare or contrast with those woodlands previously mentioned in traditional British ecological literature.