Who knows, Claire?
Among other things that have come to light, and the fact that none of us have ever been able to verify their claim that they were married in 1850 in New York, we are beginning to suspect that maybe they weren't married in the first place!
Both parties entered a second marriage after my GM was born, but the second marriage of CJD was either not known or not recognised, as it's not mentioned on his death certificate.
And he's the only person of that name that I have been able to discover in Australia in that period.

He's from France, and first wife was Swiss, second wife French. At least I have that (second) marriage certificate!

Dawn M