JOHN EDGAR AND MARGARET HARVEY COUNTY DOWN IRELAND

Searching for information on John Edgar and his wife Margaret Harvey who lived in Saintfield/Boardmills, County Down, Ireland.I know they had one son Samuel who immigrated to Canada in 1860 with his family.Would like to know if John and Margaret had any other children, their names, etc and whether they came to Canada.Also birth and death dates of Margaret and John.