I'm researching Irwin's and Davidson's in Markham from abt 1826-1870, specifically James Irwin (b.abt 1800 in Ireland) and his wife Margaret Clark. Their daughter Jane Irwin, (b.1830 in Markham) married Patrick "Peter" Davidson, a miller there. David, James, Robert, John & William Irwin, Jane's brothers, all moved from the Markham area to the Townsend, Norfolk, ON area by 1871, with their widowed mother Margaret. Peter and Jane Davidson moved to Udora, Georgina, York, ON by the same time. James Irwin senior apparently died in an accident before the 1851 census. Any connection?