It's incapable of conveying anything if the civilization is lost. Maybe the mound builders had an incredible understanding of the land, maybe they didn't, but w

It's incapable of conveying anything if the civilization is lost. Maybe the mound builders had an incredible understanding of the land, maybe they didn't, but we can't say they documented it, at least not in any way that's transferable to the future or discoverable by a foreign culture. Maybe I'm moving the goal posts and I'm not trying to do that, so I'll leave the immediate topic there.