Complex sentence: Cornelius has an extant grave marker in the Pentucket Cemetery in Haverhill; though Martha does not, the Page genealogy by Case and Sanderson (1978) states that she is buried there as well.
Split into simpler sentences: Cornelius has an extant grave marker in the Pentucket Cemetery in Haverhill. Though Martha does not, the Page genealogy by Case and Sanderson (1978) states that she is buried there as well.