In onshore areas of the British Isles, Paleogene rocks crop out mainly in two widely separated areas with greatly differing developments. Predominantly shallow-marine and marginal-marine sediments are represented in the Hampshire and London Basins in southern England; lava sheets and associated intrusive rocks in NW Scotland and northern Ireland. Marine Neogene sediments are represented almost entirely by a small Pliocene outcrop on the North Sea coast in East Anglia. Non-marine Paleogene and Neogene sediments occur mainly in small areas, except for the Lough Neagh Basin in northern Ireland (Fig. 1).
Tertiary igneous rocks of the NAIP (North Atlantic Igneous Province) have a long history of intensive study; yet, for many years, Tertiary sediments had a rather subordinate role in British stratigraphy (and in stratigraphy textbooks), studied largely by a small group of geologists, but which included several outstanding stratigraphers and palaeontologists. They outcrop in a relatively limited area of the British Isles, and were difficult to date and correlate owing to the apparent lack of ‘zone fossils’ such as the ammonites or graptolites of previous eras. Their main economic value being the exploitation of sand and clay for bricks, other building materials and ceramics, they could not easily compete with Carboniferous coalfields or Jurassic iron ores for government or academic research funding.