R. W. O'B. Knox – författare

The abundance of carefully prepared microdrawings of rock types and textures was a feature that maintained the demand for Harker's 1954 text Petrology for Students as a guide to the study of rocks in thin slices under the microscope. This 1978 successor makes Harker's microdrawings, together with over 60 further ones, available in an original petrographic text, amplifying the coverage to embrace rock types whose importance had increased since Harker's work was published. Three sections cover igneous, sedimentary and metamorphic rocks. The igneous section emphasises the use of chemical and mineralogical characteristics in the description of igneous rocks, whilst the sedimentary section covers each major sediment class, describing how to recognise and interpret individual rock constituents. The metamorphic section summarises metamorphic reconstitution and discusses the metamorphic facies classification. Each section uses the terminology and treatment resulting from specialisation in the three different types of rock.