George, There is a genealogy in the New City Library, titled SIDMAN-SIDNAM FAMILIES of Upstate New York, by Evelyn Sidman Wachter, Gateway Press, Inc, Baltimore, MD, 1981. There are many John SIDMANs and Mary SIDMANs listed in the index. This family originates with Lt George Sydenham, who came from England with the British Army during the 1600s. No John Coborn is in the Index. Bob Protzmann