The uncharted island is in the shape of a whale spurting water facing the boat. The first
one is the one in the upper right, where the tail is. The second one is the spray, so its
in the upper left hand side where the "spray" is. The third one is the fin, so the bottom
middle one on the elevated surface. The last one is the eye, the first one you see if you
go up a little coming to the cave from the boat. As soon as you finish that, a bridge will
appear and allow you to go in the cave. There a large belly-buttoned frog will give you
the cyclone slate. Fyi: i did this earlier than the game wanted people to, which is after
the 3rd temple. I did it as soon as i got the sea chart. P. S. It helps to explore
everywhere on the sea chart before you do something. It really helps a lot.