Jan Mayen, so far as at present known, is entirely volcanic in origin. The rocks, therefore, are conveniently grouped with the Tertiary and later volcanics of the Faroes, Iceland, and Scoresby Sound in East Greenland. It should be noted, however, that these three localities are linked together by the Faroe-Iceland Ridge, the water everywhere being shallower than 500 fathoms. Jan Mayen, on the other hand, though lying at the same distance from Iceland as the Faroes, is not on the Ridge, and is separated by depths of over 1000 fathoms. Its position is somewhat to the west of the centre of the Norwegian Sea, and at no great distance from depths exceeding 2000 fathoms.