Skyrim Secondaries- Forbidden Legends: Very Unusual Size

The first one, at the bottom of the stairs, needs to be an Eagle, the second (encountered before the stone table) should already be on its proper setting of Whale, the one under the mammoth skull should be set to Serpent, and the last then needs to be turned to Whale facing.

With the obelisks in their correct settings, the lever will now operate the porticullis and you can proceed up the stairs to a drier part of the dungeon.

At the far end of the passage you enter here is another room with ankle-depth water, and it's guarded by a number of draugr.  Three of them can reach the same areas as you- a wooden stair leads up to a nook on the far side of the room where two of them wait.  A fourth draugr can be found on the circular ledge surrounding the room's main pillar, overhead of the main floor- this one is a Draugr Wight and fairly tough, but it thankfully can't really reach you from its location.  Entertainingly, you can shoot it with a bow or ranged spell from the nook, making it an easy target.

On the lowest level of this room you can pick up still more fungus, some leather strips, and a potion of stamina, whle the recessed area up the first stairs holds a few more treasures and the corpse of Archmage Geirmund, as well as the paper upon which his epitaph is written.  The epitaph notes Geirmund's place as a guardian in death of the three traitorous brothers.

The door behind Geirmund's resting place is locked, and behind this wait another draugr and a skeever- take out the zombie first, as it usually puts together spells and a weapon in deadly combination, where skeevers are simply annoying ROUS's.

The path splits here, but the right hand stairs are obstructed by a rockfall.  Head up them anyway to get a touch of treasure and a small potion, as well as a look into a room further on in the dungeon.  Then, return to the path split to check out the enchanting table, which may be useful if you've found yourself hauling around some gear you want to learn the magic for.

Head the other direction past the enchanting table, ignoring the short dead end to the right, and you'll locate stairs heading up to the  left.  Take care as you go, because a Draugr Scourge lurks in the small room at the end of the stairwell- while he does start out facing away, he will quickly turn to you and start unleashing Fus Ro Dah shouts at you.  If you're of an appropriate level (20-25) then this is going to be more debilitating than deadly, but you may well find yourself retreating down the hall during the fight anyways.