Complex sentence: During much of the seventeenth century, Pemaquid (present-day Bristol, Maine) was the most northern coastal settlement of New England, and Pentagouet (present-day Castine, Maine) was the most southern Acadian settlement, a colony of New France.
Split into simpler sentences: During much of the seventeenth century, Pemaquid (Bristol, Maine) was the most northern settlement of New England. Castine was the most southern Acadian settlement, a colony of New France.