The McMurtry Clan

I am seeking information about William Babcock (12/20/1811-4/24/1875) born in New York who married Sarah (Sally) Maria McMurtry (3/17/1816-2/4/1896) born in Monroe, Orange, New York, both buried in Sloatsburgh, New York. They are both my 3 GG. The male ancestors for Sarah seem to be named Alexander for at least 3 generations before her. For years I have been at a brick wall with William Babcock. Thanks for any help with him or Sarah. Don Babcock, Chesapeake, VA