I have, Michael 1828 - 1918, Mary 1829, Dan 1834, Peggy 1837, John 1846, Patrick 1850 and Henry 1852.
My 3 x great grandfather was John Convery 1807 Maghera Derry. He married Mary McCollough also from Maghera.
I don't know if there's any connection with your John though.
Good Luck!