Marcus, Marquis and Boyd

Looking for the family of Daniel Marquis\Marcus in Irvine, Ayrshire. He married Grizel Boyd on 1 December 1765 in Irvine. Her family line goes back a few generations in Irvine.

Daniel Marcus seems to have come out of nowhere.

Children: Ann, Daniel and James Jack all born 1768-1777. No other known children.

Anyone researching the Marcus\Marquis family?