Either like Worth 55 said " 2 different houses" or one big L shaped one. the other foundation could be a barn. Like everyone else said Dig It!!!!!!!
Then let us know what you find
Your first pic looks exactly like a foundation I hunt. Mine was an old railroad station, what you see are two separate foundations (there may be more) that held up a single elevated building. DO you have any old railroad tracks near the site? The dual chimneys in the clearing could be railroad related as well, I would think.
I don't know about the foundation but the chimneys have a bunch of structure info to offer. You can see the peak of the roof on the nearest one for example. Do a little research and happy hunting.
be real careful around the chimneys. my buddie was standing right next to one made of stone when it fell. crushed a wheel barrow into the ground.
he was burning brush at the opening and the overly hot fire weakened the round bar 3" in diameter that was serving as a lintel. there was no warning, he said he felt the thud.
i've seen old house with two, opposite facing, chimneys?