3 Geological units defined on the basis of material content or other physical properties
3.1 General properties and arrangement of the rules for the units
All categories of geological units in this chapter are defined on the basis of various material properties (lithology, fossils, magnetism) and/or other physical properties (boundary and contact relationship, form, structure). The categories dealt with are lithostratigraphical units (Section 3.2), lithodemic units (Section 3.3), magnetostratigraphical units (Section 3.4), biostratigraphical units (Section 3.5), pedostratigraphical units (Section 3.6), geological form units (Section 3.7), linear structural units (Section 3.8), planar structural units (Section 3.9), morphostratigraphical units (Section 3.10) and tectonostratigraphical units (Section 3.11), (see Table 1 and Figure 1). Seismostratigraphy is briefly described (Section 3.12). Each unit is dealt with under 9 main headings:
1. Basic definition
2. Rank, and the position of the unit in a hierarchical system of division, if any
3. Dimension and extent
4. Mappability and methods of identification
5. Content and other properties
6. Nomenclature
7. Variants of the unit, relationship to other units, supplementary comments
8. Examples
9. Key references
