In 1968 the average salary of men teachers in maintained schools in England and Wales was Â£1,646. I estimate that the last two pay settlements have raised this figure to about Â£1,880. The comparable figure at 31st March, 1963, was Â£1,244.
Two main tectonic structures are spreading centers and subduction zones. Spreading centers occur at the boundary between two plates that are moving apart, called divergent plate boundaries. Here the plate motion opens a gap between the plates and magma from the mantle rises up through it.
Concurrent range zone and partial range zone (ISG, Figure b and c): The interval between the documented lowest occurrence of one taxon and the documented highest occurrence of another taxon. Concurrent range zone is used when the fossil occurrence results in stratigraphic overlap of the taxa (Figure b).When such occurrences do not result in stratigraphic overlap, the interval zone may be called a partial range zone (Figure c).3. The zone, or biozone, is the fundamental unit of biostratigraphic classification. A zone may be divided into subzones and/or grouped into superzones. Each biozone is given a unique name, which is compound and designates the kind of biozone.