Last time we ventured a bit out of town to view this Mystery Spot, which as BF and Phantom Railfan correctly guessed is the Saline Depot. As you know the structure still exists and is a museum, one of two maintained by the Saline Historical Society. The other museum is the Depression-era farm the Rentschler Farm.
This time we're back in town, but it's a tricky one since this building is long gone. According to the blurb accompanying this engraving, "It was originally erected for a hotel in the "boom" times of the early thirties; but after the financial crash of 1837 it was a dead property until [something] was established in the fall of 1844."