Family lore would indicate that she married a Dr. Pfeiffer, but neither her obituary not her grave marker include that surname, making this information questionable.
OBITUARY in the New York Times;
"Field-On Thursday, Sept 17, at Fort Hill, Scarsdale, N.Y., in the 26th year of her age. Mary Stone Field daughter of Susan Andrews and the late Cyrus W. Field Jr. Funeral private."
Mary Stone Field
Sep 17, 1908
Sponsored by Ancestry