Mccullough, Lucy M
Lucy is shown in the 1880 census as Lucy M.. In her mother's obituary, 1908, she is only named "Miss Lucy", together with unmarried sister Ella. After 1880, there are no records for a Lucy M.. However, a Lucy B. shows up first as a servant, then as a registered nurse. She is buried in the same cemetery, with the same type of headstone as (and from the appearance, probably next to), Ella G., and the inscriptions on both say "sister". My conclusion in the absense of any other records is that Lucy M and Lucy B are the same person, daughter of David Ross McCullough.