Golden Sun: The Lost Age/Madra Catacombs

Go down out of the ladder room and go around to the top door. In the next room, go up and climb down the ladder. Go out the bottom of this room. You'll be in the ruins of whoever the ancestors of the Madrans are. Anyway, go in the hole in the wall next to the door you came through and climb up the vines. Use Move on the pillar to drag it into the hole so you can walk across. Go down the vines and enter the building. There's only one path you can take for the mean time, so follow it down the stairs and keep going until you reach a chest. Inside is the Tremor Bit, which you should equip on Felix. You can't use this power yet, so Retreat from Madra Catacombs and exit Madra onto the world map. Go east to find Madra Drawbridge.