"The Leland Emerson Magills of Mass"

I have just begun to research the Magill Family History. Starting with my Grandfather, Leland Emerson Magill born 1917 in Michigan. I have several generations on the Magill Family going back to my Great, Great, Great Grandfather, Samuel Magill who was born @ 1839 in Scotland. I know from a Mass 1900 cencus that my Great, Great, Great Grandmother was born in Ireland possibly around the same year, but her name is unknown to me. I am continuing to research as much as possible, and any information that may be out there would be helpful and appreciated.