I found the death certificates at the the New Jersey State Archives in Trenton, NJ. They are not my family.
My gg-gmother Mary DULLARD was born in Ireland abt 1836, the daughter of John and Mary Dullard [parents from death cert]. Mary married John CAVANAGH (son of Daniel and Ellen) before abt 1854, perhaps in Ireland. Their first known child Ellen (m. CONDON) was born in Paterson, Passaic Co., NJ abt 1856. Other known children (all CAVANAGH) were Mary (b. abt 1858, m. FARRELL), Daniel (b. abt 1866, never married), Honora (b. abt 1868, never married), Margaret (died 1869 age 1 month) and John (b. abt 1871, may have married). Mary (nee DULLARD) died in Paterson in 1882.
There was a Daniel DOLLARD listed in the 1859 Paterson City Directory at the CAVANAGH address - it was the only year he appeared there. Don't know what happened to him or who he was.
There was also a Thomas and Janet DOLLARD who lived in Paterson at least 1855-1857 and in Jersey City at least 1867-1870. They had 5 children:Thomas (b. 10 Apr 1855 Paterson), unnamed female (b. 8 Nov1856 Paterson), Edward (b. abt 1858-59), Mary C. (b. 9 Mar 1867 Jersey City) and Ellen (b. abt June 1870 Jersey City?). I don'tknow what happened to any of this family.
I assume that Daniel and Thomas DOLLARD may have been related to my Mary DULLARD, since all 3 appeared in Paterson at the same time.