Two fine inlets, Berkeley Sound and Port William, run far into the land at the northeastern extremity of the island.
They are placed on a line joining the north end of Sumatra and Cape Negrais, the south-western extremity of Burma.
On its western extremity it is linked by secondary ranges to the mountain system of Morocco.
In Heliodrilus the blind extremity of the spermatheca is enclosed in a coelomic sac which is in connexion with the sacs envolving the ovaries and oviducts.
Two other states on the northern extremity of the island were so far devastated by the Tambora eruption of 1815 that their territory, after lying for long uninhabited, was in 1866 divided between Dompo and Sangar.