I am a Gravlin as well, although no telling how many generations separate us! There are multiple spellings of this last name, and oodles of branches! Urbain Baudreau Gravelines is considered the family patriarch. He had 8 children, and each of those children pretty much did the same thing many times over, so it's a huge clan.
My mother and I belong to the Urbain Baudreau Graveline Genealogical Association, to which I'm sure your family belongs. And to see the members, most of them have the same Gravlin nose!
I have many back issues of Les Descendants, our family genealogical magazine. I will search through them and see if I can find a connection to your family somewhere.
Urbain was a Frenchman who came to New France (Quebec) from Clermont, France in the 1600s. He was a syndic in Montreal, and had 8 children. My branch is descended from his youngest son Jean.
Let me see what I can find and I will get back with you. If I find the info, I can send it to you.
If you'd like to contact the Association to become a member, their address is:
PO Box 905
Palmer Massachusetts 01069