Help with last name

Would anyone be able to assist me with the last name of Michael Burke's mother on a death certificate - 

I dont know where in Ireland they are from yet - Hoping to find some records with his mothers last name 

This Michael Burke married Margaret Welsh / Walsh and lived in New Jersey (not sure of the exact date) around 1873

Michael's date of birth varies with each US Census - Somewhere between 1850 - 1855 

Margaret's date of birth is the same around 1854-1856 - Michael shows arrived in 1855 and Margaret 1874 

Margaret passed away in 1913 and Michael passed away in 1924 

I have attached the death certificate