This is a difficult question, because it is very map specific, and requires us to search our memories. I remember a stone circle at the end of the beach area, and there is a cave entrance near it. Have you found the cave entrance? I had some trouble noticing it. The cave is to the right of the circle, and I don't think you proceed by going to the left of the circle.
Try to find the cave entrance, go in, and see if that lets you proceed.
[color="Gray"]"They who can give up essential liberty to obtain a little temporary safety, deserve neither liberty nor safety." Ben Franklin [/color]