They heat to southwest, deeper into the sea. Once they've traveled half an hour southwest, they will purely go down. It takes them two long hours to get to the cave they've looking for (all in all, two and half hours).

The cave is huge and it's full of more elven language writings that seem to tell a history of the elven people. There are pictures drawn next to the writings, showing different sized elves doing various things, like courting one another or farming. Then there are various weird symbols spread across the walls.