By the look of the entry in her marriage cert., it is probable that Margaret Ogilvie's parents John OGILVIE and Janet MCNEILAGE weren't married when she was born. This is Margaret's IGI entry:
MARGARET OGILVIE Birth: 08 MAY 1838 East Parish, Greenock, Renfrew, Scotland
Parents: Father: JOHN OGILVIE Mother: JANET MCNEILAGE
This looks like mother and daughter Margaret in 1841, from FreeCen:
MCNEILLYE Mary, 50, Independent, b. Outside Census County
MCNEILLYE John, 30, Ship Carpenter, b. Renfrewshire
MCNEILLYE Janet, 25, b. Renfrewshire
OGILVIE Margaret, 3, b. Renfrewshire
PATERSON Robert, 15, Carpenter Appren,b. Renfrewshire
PATERSON William, 15, Carpenter Appren, b. Renfrewshire
SOMMERVILLE Anthony, 15, Carpenter Appren, b. Renfrewshire
CAMERON James, 25, Stoker, b. Outside Census County
LENNON John, 40, Independent, b. Outside Census County
ROBERTSON John, 35, Independent, b. Outside Census County
Address: 23 Arthur St, Greenock-Renfrewshire
Regards.
Monica