Due to a well-known bug, the
Greenland Dungeon doesn't normally appear in the
Pangea era. Of course, it's the same
Greenland Dungeon that appears in a number of other eras, so it's not really a big deal. (There is a slight difference in the layout of level 15, but it is otherwise identical.) It
is most easily accessible in
Pangea, but in terms of both normal treasure and
Tri-Lithium, this is a pretty pitiful dungeon to delve.