Heather's journal?
Back when the Blair Witch Project came out, there was a section that included the contents Heather's journal. It said it was found "buried beneath a 100-year-old cabin in the woods."
http://www.blairwitch.com/project/journal.html
That witch's house would be much older then 100 years old since she was cast out of Blair in the 1700s, and in this movie James says the police (or search parties?) never found the house anyway.
It also couldn't be Rustin Parr's house since James says that it was burned down after he was charged with murder which was back in the 1940s. It wouldn't be old enough anyway since Parr built it himself, but it would be closer to 100 years than the witch house.
I don't recall there being another cabin that they dropped by in the first movie...
So where the hell did the journal come from?
Is it just a case of botched mythos?