Factual error: When Chris Farley is climbing up the side of the mountain to return the bird egg, you see the bottom of his moccasins and they appear to be made of a ribbed (for traction) material. Back then, they would have been made from animal hides and the bottoms would have been smooth not ribbed.jaws65
Revealing mistake: When Mathew is looking at the stars and his telescope falls, the wire that is attached to the telescope is visible.
Other mistake: When Bidwell comes back from being mauled by the bear, he has a wooden "crutch". When you see him up close the crutch is sawed or finely cut on the top. He was lost in the woods so I don't think he could find one of those.
Factual error: In the final scene, when Mr. Hunt is planting the flag in the beach, we see the original 13 star pattern, and another larger star in the middle. However, in 1804, there where already 17 states in the union, so the flag should have 17 stars.