I never would have figured it out.
There was an old British TV show in the '90s called "Time Team". It was a group of archaeologists that would go dig a specific site - usually one ignored up until then - and try to locate a medieval manor or a bronze age village or whatever in a weekend. One of the guys, a fellow named Stewart, was didn't dig, he scanned the ground. He would walk around making notes and then come back and say 'there was a river over there 1,000 years ago, those slight bumps (everyone would say 'what bumps?') were battlements, and the gatehouse would be over there in the small depression.'
Everyone would laugh and ignore him and by the end of the episode, 9 times out of 10 they'd relent and dig where he said and lo, he was right all along.