I don't know if this will help as I suspect that we are from two different families but here is what I know (which is fragmentary):
In the early 1800s there was a Roger Dea who apparently emigrated from England. He had at least one son, Roger Dea born abt. March 1819 in New York.
Roger jr. moved back to England where he met and married, the wife's name was either Mary or Elizabeth. He returned to America and died on April 2, 1893 in Union Grove, New Jersey. He had at least two sons, Harry (who died as a teenager) and Edward John.
Edward John Dea married Christine Baxter and they lived in Jamaica Plains and Boston, Massachusetts. They had seven children: Roger, John, Edward, Thomas, Robert, Henry and Christina. I don't know if any of these moved to New Jersey nor do I know of a Ralph Dea.

- Douglas Dea