Robert McKeen or McKean

[wjmilne]

I seek inforfmation on a Robert McKeen or McKean, Born abt 1835,Antrim.
First appeared 1859 in Ayr,Ayrshire,Scotland,as a policeman on marriage to a Jane Drennan.
He gave his parents as William John McKeen and Jane White.His father's profession as farmer.
All records forwards from his aforementioned marriage in 1859 are traced & he died in Ayr.
On one police application form he gave his birth place as "around Antrim".
Research from Essex,England, has revealed nothing and this is my last hope.