This quest was marked obsolete by Blizzard and cannot be obtained or completed.
Destroy the Altar of the Tides with Catelyn's Blade, kill Gazban and bring the Stone of the Tides and Catelyn's Blade back to Baron Revilgaz.
So you're looking for an altar of some sort? Well, I'm no expert on troll ruins like my father, but I have heard about a sunken troll city out near that island you're looking for. Maybe you should try there.
You got my knife back for me, so I guess you can borrow it... but I want it back when you're done!
Amazing! The Stone of Tides! It shall have a place of prominence in my collection of ancient troll artifacts. Did you see how it almost seems as though a tide is trapped within its surface? Magnificent!