Isaac R Downing was the son of Silas Downing )1806-1856) and his wife Elizabeth Boyd (181-1896). Myrtle Little Sheff (1869-1929) had a father born in NY stae and a mother born in England. She graduated from the State Normal College in Albany and taught for four years in locust Valley. Raymond Little Downing was their only child. He studied medicine at the University of Pennsylvania but did not graduate.
I do not know if he had any children.
They all lived in Glen Cove.