Alright it's really tricky to find. if you go up to the top of the tower, you can see it from up there if you look. I think it was on the right side but my friends are the ones that got it, but they had to go up to the tower's top to see it.
Midway up the waterfall on the right is a small green item [forget what it is] that opens a hidden area. Find the X on the ground to reveal the hidden chest. --- Currently Playing: Borderlands 2, Fez, Mass Effect 3 Gamertag: TheMathWhiz