Geology

A concise manual presents geology as the study of the earth's crust, its materials, and the changes of land, water, and climate through time. It defines rocks and minerals, outlines a practical classification into mechanically formed (sedimentary and aeolian), chemically formed, organically derived, metamorphic, and igneous groups, and treats petrology and common rock-forming minerals. Structural topics include bedding, joints, cleavage, faults, unconformities, and modes of occurrence of intrusive and metamorphic masses. Chapters survey agents of change—atmosphere, running water, biological activity, and subterranean forces—followed by discussions of metamorphism, physiography, palaeontology, historical geology, and examination questions for learners.