SHINGLE HOOKS
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may even spread to form a continuous covering. The establishment of additional species will depend on the opportunities that occur for the bringing of seed, and whether the sea has regular access. In the latter case it is likely that the low will develop into a salt marsh.
   Before leaving the dunes of the Headland a general view of the large Salicornia marsh should be obtained, preferably from the sand-hill south-east of the Laboratory on which the fifth telephone pole from the Boat House stands. This point commands the whole expanse of this marsh, some 60 or 70 acres in extent, occupying the flat ground between the dunes of the Headland and the Long Hills Bank. In summer it consists of a green carpet of Salicornia annua, with which is associated the unrooted and sterile libera form of the brown seaweed Pelvetia canaliculata. Covered by nearly all the spring tides this marsh represents an early stage in the development of a salting. Observations show that the level of the Salicornia marsh is rising yearly from one-half to three-fifths of an inch in its middle parts.
   On its north-west side the marsh is divided into bays or compartments by four or five low shingle beaches, conspicuous objects from the view-point (Plate XXIII). These beaches in the history of the development of the Point must formerly, each in turn, have represented the organic apex of the whole system. Successively they were deflected into their present positions before the main platform of the Headland had been formed, and as each hook was overtopped by the next one formed it would be screened from direct impact of waves and pass into the dormant state. The long hook which closes in the Salicornia marsh, separating it from the main estuary, and which runs from the Lifeboat House to beyond the house-boat Britannia, is still mobile. Evidence of its recent marshward travel is afforded by the stools of Suaeda bushes still persisting some yards outside it; originally these bushes grew on the inner fringe of the beach, which has passed completely over them.
   The hooks which project into the Salicornia marsh are typical of the whole system of construction of Blakeney Point from the Marams to the Life-boat House. The accompanying