This is an essential guide to geology and the earth sciences for both students and the general reader, now with the addition of details of useful websites to help you take the subject further. This edition of the "Collins Dictionary of Geology" is a fully comprehensive and up-to-date dictionary of geology, encompassing all the major areas of study in over 4500 entries, making current terminology accessible for the general reader while retaining the breadth and depth of explanation required by students of geology. It offers comprehensive coverage of geology, including palaeontology, geomorphology, sedimentology, mineralogy and geophysics. With consideration of the practical and economic aspects of geology, it contains extended features explaining key topics such as dating methods, fault, igneous rock and seafloor spreading, enabling these key concepts to be put into context. Internet links help you explore the subject further. It has examples of geological phenomena from throughout the world, and includes helpful line drawings and diagrams. The book has been prepared by authors with a wealth of practical teaching experience with students and in adult education, making the text accessible both for students studying geology, earth sciences and geography and also for the may enthusiastic amateur geologists. Sample entries are: Jurassic - the period of geological time extending from 210 to 140 million years ago, occupying the middle portion of the Mesozoic Era between the Triassic and Cretaceous periods. Its name refers to the chalk sequence in the rock strata of the Swiss-French Jura Mountains; Pele's tears - cylindrical, spherical, or pear-shaped drops of glassy basaltic lava from 6 to 13 mm long, named after the Hawaiian goddess of volcanoes and fire; Summit accordance - the equal or nearly equal elevation of mountain summits or hilltops over a certain region.