Allexperts Geology - Geologists answer submitted questions about geology.
Earth Science World - American Geological Institute resources for teachers and students. Includes searchable database of earth images, geologic time scale, and interactive features.
Evolving Earth Foundation - Earth science and natural science resources, articles and online education.
Geography Site: Physical Geography - Illustrated descriptions and explanations of earthquakes, plate tectonics, glaciers and glacial landforms, and volcanoes and volcanic deposits, intended for students up to age 16, but suitable for a wider audience.
Geological Society - General geology portal site, including links, products, and a discussion forum for professionals and students.
Geoscapes Photography - Geologic and natural history landscape photography of the western United States and Pacific islands.
Pangaea - An information system aimed at archiving, publishing and distributing data from global change research with special emphasis on geological, marine and environmental sciences.
Planet Earth: An Introduction to Earth Sciences - Online text by Roger N. Anderson of Columbia University. Covers origins of the earth and life, plate tectonics, and formation and deformation of continents.
Strata: William Smith on the Web - Publications of the father of modern geology, who first drew a chart of the strata under the surface of the earth. Printable version of Smith's famous geologic map of England.