Numerous small islands lie off the western coast, but none has any commercial importance.
A number of islets (Nako, Bunga, &c.) lie off the west and north coasts.
A closer investigation of the numerous long, narrow banks which lie off the Flemish coast and the Thames estuary shows that they are composed of fragments of rock abraded and transported by tidal currents and storms in the same way that the chalk and limestone worn off from the eastern continuation of the island of Heligoland during the last two centuries has been reduced to the coarse gravel of the off-lying Dune.
The principal islands lie off the south coast.
They are apparently volcanic. Coral reefs lie off the coasts and render them difficult of access.
