Where is the 2nd bell in dark souls located

From the Depths, you go to Blighttown with the key you get from defeating the Gaping Dragon. Then you eventually get to a swamp, and Witch Queelag's lair, (Which has huge monsters waiting to throw boulders at you around the entrance). This is the boss that you have to beat. After she's defeated, you go into the room opposite and ring the second bell.