Do some research. It only took me 2 minutes to find a picture of the chest and it's contents as Fenn was deciding what should go in it before he hid it. From what I could see, it was mostly gold, watches and gems but he took some things out and added others before he closed the chest up for good to hide it.
He was a successful author and probably didn't need the money and this gave him a real life treasure and mystery to be involved in.
Chest Full of Gold