Myself and a friend were exploring and gathering flightpaths when we stumbled across this. It reminds me of the rim in the Discworld a little. Its probably already known, but I can't search, and I've checked back a few pages to see if I can see anything like it, but nothing jumps up at me. Apologies if its a repost.
I can post a guide for getting to this area if anyones interested enough to request it, and I've found its also a quick way of getting from the stonetalon mountains, to darkshore - although you have to deal with rez sickness, so its not immensely handy.