cannot find forgotten halls location. help

Merah, T2 is the only game I'm playing for now, but it's been several days since I passed through Forgotten Halls my last time in Act 3. What I do recall is that it doesn't show up until you do several previous quests along the main quest line. I don't recall which areas are required before then, but here's a list of the dungeons I did on the Sundered Battlefield map before Forgotten Halls the last time I was in Act 3. I show them in the order in which I did them. Sorry, I don't recall the names of quests needed.

(Note: I previously had listed Vyrax's Tower as the 1st dungeon, but I since realized that it's the last dungeon I had done in the Riverskull Gorge map, & not the 1st one in the Sundered Battlefield map.)

1. Phase Portal: no quest needed.

2. Neatherrealm Portal: I think this one is always visible (that is, no quest needed), but I may be wrong.

3. Cocklespit's Realm: This is one of the required quests along the main quest line. But I think you have to find the witch Cocklespit and do her quests first. She's on a previous map in here in Act 3. I may be wrong, but I think you had to have found her & did her quest on the other map before the Sundered Battlefield is opened for you.

The only way to get to her "realm" here in the Sundered Battlefield is by talking to a shade (ghost) named Fade who has a ghostly carriage with him, which he uses to give you a ride to her "realm". After you defeat Cocklespit, the exit takes you back to Fade, once again outside of her "realm". But you must then re-enter it, because now a hidden route is revealed to one of the Robot parts that is back in her "realm". Those parts are all needed also to advance the main quest line. However, I can't recall if you need to find all of them before or after Forgotten Halls.

If I recall, Fade & Cocklespit's Realm have always been along the west edge of the map.

4. Elemental Oasis: This only appears after finding 4 elemental crystals scattered about the map of the Sundered Battlefield. Not sure if it's part of the main quest line, but I don't think so.

5. Forgotten Halls: This dungeon entrance was now visible and I did it. The only dungeons that I hadn't done yet in the Sundered Battlefield map were: Emberworks and 3 Sisters, so at least those 2 were not required beforehand.