The Alaskanisland called New Eddystone Rock is a pillar of basalt. The basalt came from fractures in the floor of Behm Canal in the last 5 million years. The broken, haphazard texture of these basalts indicates that New Eddystone Rock was part of a volcanic vent where magma rose repeatedly to the surface of the earth.
When in its molten state, the basalt was very liquid, so that it spread out over a large area, like pancake batter on a griddle. These flows cooled from both the top and the bottom forming the hexagonal columns which are visible on several of the islands surrounding New Eddystone rock. After the basalt flows covered the floor of Behm Canal, another glacial advance scoured away much of the flow, leaving behind New Eddystone Rock and some of the islands to the northeast.