Complex sentence: Her father was plantation farmer William Walter Woolsey (born July 18,1842) whose family, the Woolsey branch of the New England Dwight family, had influence in the law, the church and education.
Split into simpler sentences: Her father was plantation owner William Walter Woolsey (born July 18,1842). The Woolsey branch of the New England Dwight family, had influence in the law, the church and education.