A model of the formation of the Chichester tidal delta has been developed, and was referred to (Harlow 1979), but the mechanism was not included in the present paper due to space limitations. The formation of the double recurved spits, the paired sand banks raised above MLW and the natural bypassing of sand and pebbles around the delta by tidal currents, wave refraction and littoral drift were all considered. A littoral drift around the Chichester tidal delta, feeding the beaches of Hayling Island, is clearly implied from the sediment budget flow diagram (Fig. 5) and from the high rate of littoral drift fed ashore on Hayling Island (Fig. 5).
‘Hayling shoal’ is not simply a recurved extension of the Langstone tidal delta, for it is a rock outcrop. It may either be in-situ rock, or a glacial erratic, or the foundered remains of a shipload of stone to Chichester Cathedral, or even the lost ruins of a former church on Hayling Island.
Despite a superficial resemblance to Gunner Point on Hayling Island, Southsea Common on Portsea Island is not a Cuspate foreland. Although it is shown as a shingle deposit on the one-inch Geological map, the Common does riot display the shingle ridges which are so prominent at Gunner Point, and there is no evidence to suggest that they have been artificially levelled in the past. Secondly, the Portsea beach is above the level of the flat Common, unlike the Gunner Point ridges which rise towards
- © The Geological Society, London 1980