need help locating great great grandparents

hi there my name is georgia,y dadi've been searching on/off for numerous years trying to traced my dads  family who came from ireland,my great grandfather was terrence m gallagher his parents were thomas and nora no maiden name given,my great grandmother was bridget dean her parents are listed as thomas dean and honora reddy,according to research done on rootschat they have terrence birth yr between 1820 and 1840,bridgets death cert which i have from rhode island states she was 70 yrs old when she died in 1921.so i calculated her yr of birth as 1851 but rootschat said its much earlier,.bridget and terrence had many children i believe 5 were born in ireland the rest in the US, children are mary,patrick f,ann,nora,terrence jr,thomas,ellen,margaret,and kate,pat,rancispat gallagher born around 1864,co.mayo ireland,patrick francis born 1866,thomas 1875, terrence jr 1878,mary around 1887,rose around 1870,my grandmother margaret born around 1882,i only have 2 baptism listed 1 being patrick on 5-12-1864 sponsors being hugh and ann scanlon, 2nd baptism honor gallagher also known as nora baptism 11-15-1868 sponsors also being hugh and ann scanlon, patricks wife is listed as maryellen mcglynn 6-14-1888, thomas gallagher married annie e newman 1878,if anyone could help me with any of these particulely bridgets and terrences parents i would be grateful