Complex sentence: The mill was located at a place commonly called the "Falls" of the Pequonnock River beginning in 1674, at present it is the town boundary with Bridgeport called "Fairchild Park".
Split into simpler sentences: The mill was located at a place commonly called the "Falls" of the Pequonnock River beginning in 1674. This site is now the town boundary with Bridgeport called "Fairchild Park".