Thanks to some wonderful information received today, I have proof of the father of Sinclair Alexander Robinson as indeed William Robinson. The marriage certificate listed a Sophia Rebecca Powderly and John Joseph Hamerton as witnesses. Sophia's parents are John Joseph Powderly and Nannie (Nanny) Robinson.
Other siblings to Sophia are Thomas b. 1865, Alexander b. 1867, Margaret b. 1870, William John b. 1866 and William John b. 1879.
As witnesses were usually relatives or close friends, any help would be apreciated to see if Nannie Robinson is related to Sinclair Alexander Robinson. This is the closest lead I have had since searching for the Robinson side of the family. Thank you for any help.
