Just a possibility, but the 1851 Scotland census shows a 30 year old bricklayer Thomas Cowan and his 28 year old wife Lucinda, 8 year old son Thomas, 4 year old son William and 1 year old daughter Mary Jane, living in Mauchline, Ayrshire. All were born in Ireland bar Mary Jane, who was born in 'Ayrshire Mauchline'.