The North Sea is not renowned for its islands, and much of the modern land–sea interface is sharp, especially along the coasts of Jutland, North and South Holland and much of England. Nevertheless, the North Sea does contain a surprisingly large number of islands and archipelagos, which can be presented with reference to a clear north–south divide. In the northern half of the North Sea, most islands are of hard rock with shallow soils, and their islandness is the result of ongoing glacio-isostatic uplift of previously drowned lands and sea-level rise. With the exception of the Shetland and Orkney archipelagos, few of these islands are found at a great distance from the mainland, and the majority of the countless islands, islets, and rock outcrops off the North Sea coasts of Norway, Sweden, Scotland, and north-east England can be found within a few miles of the mainland. In the southern half of the North Sea, the islands are mainly made up of sand and clay and, in their history if not today, were frequently sandbanks formed by the sea utilizing both marine and riverine sediments. Most of the islands of the Wadden Sea in Denmark, Germany, and Holland are sandbanks elevated by aeolian-formed sand dunes. Further south, the core of the large islands of Zeeland is principally formed of riverine sands and marine clays intercalated with peat, reflecting coastal wetland conditions at various times in the Post-glacial and Holocene (Vos and Van Heeringen 1997). As with Zeeland, the islands on the English side of the North Sea, such as Mersey Island in the Blackwater estuary and Foulness Island in Essex, have now been incorporated into the mainland. Only a few islands cannot be so simply classified:Helgoland in the German Bight, a Sherwood Sandstone stack of Triassic date, is the best known example. Island archaeology, as we have seen (chapter 2), has for many decades approached islands as environments that were relatively isolated from the wider world.
Observations on Nephrops norvegicus (L.) and on an epizoic population of Balanus crenatus Brug
