'The Barnum Family' shows him as a son of his grandfather.
From the Olean Evening Herald, Olean, New York, May 14, 1919: Word has been received in Olean of the death of Oscar Pliny Barnum which occurred April 27th at Oakland, California following a stroke of paralysis in January. It was learned that after being stricken, Mr. Barnum was drawn around the house in a wheelchair and it was not until April 12th that he suffered a second stroke which caused him to grow steadily worse, ending finally in his death. The letter telling of his demise states that he passed away peacefully like only sleeping. Mr. Barnum is survived by is wife and his son Coit Barnum. He will be remembered by the older residents of Olean as he resided on this city for a number of years where he was employed as a licensed pharmacist in the Blakeslee Drug Store. He was man of great refinement, of irreproachable character and a fine friend to those with whom he was intimate.