Dear Jan
I can understand your confusion, compounded by my error over the two Peter McFarlane Blacks.
Peter McFarlane Black (1870) and Sarah Duffy Logan (1871) had five children, not three. They were: Thomas, Christina, Henry Logan, Peter McFarlane and Mary Craig Steel (1910-2005). Mary was my mother. There was quite a wide span in the children’s ages, such that Tom’s son, also called Tom, and my mother were of a similar age and grew up together.
I am in touch with all of the current descendents of the family, apart from the branch starting with Thomas (1894), to which you are linked - so am very interested in swopping information! A Personal Message has my contact details.
Best regards
Robert