This leading dictionary--now in its third edition--offers wide-ranging and authoritative coverage of the earth sciences and related topics. In more than 6,250 clear and accessible entries, it covers geology, oceanography, paleontology, mineralogy, volcanology, and planetary science as well as climatology, geochemistry, and petrology. The third edition is fully updated and includes additional coverage of process geomorphology and physical geography, plus more than 50 new line drawings to accompany descriptions of forms and processes. The new edition also features web links accessed via a companion website, featuring additional information that is regularly updated to ensure that it stays fresh. Finally, the book has a revised bibliography and a number of appendices that include a revised geological time scale, stratigraphic units, lunar and Martian time scales, wind-strength scales, and SI units. It is an essential reference for students of geography, geology, and earth sciences and in related disciplines.