West Sussex has a wealth of geological interest although exposures are not always
easy to find or are tidally dependent around the coast. All our rocks are sedimentary
in origin and often fossilferous. For more information, see the Sussex Geodiversity
web site or my notes here.
Earth movements have subsequently folded the layers of sediment, creating a giant
upfold known as the Wealden Anticline with a central axis running east-west through
the northern part of the county. The Wealden Anticline is complicated by various
minor folds but generally the older rocks are found to the north of West Sussex and
progressively younger rocks to the south, with the youngest at Selsey Bill.
Due to copyright issues, I can’t reproduce a modern geology map here but the map
below is reasonably accurate. An excellent mapping facility is provided by the British
Geological Survey here and if you have a smartphone, then you must try their new