I started looking into the Mulvaney/Rothwell side of the family again, after spending a while concentrating on the Toners. When I asked Betty and John what they knew about the Bridget Rothwell, the answer was essentially "not much." However, they did mention that Nana used to say that she was from "the only poor Rothschilds," which seems to be an ironic reference to Bridget's family. We can't be sure, though, whether she was mistaken about the name, or just commenting on a well-known name similar to her grandmother's name, or whether, perhaps, Bridget's name really was Rothchild or Rothschild. It would be an unusual name for a Irishman, sure.
So anyway, I went looking for our Bridget Mulvany, searching Ancestry.com on her married, not her disputed maiden name. And I found this immigration record, from November 13, 1851, from the ship the John Hancock:
I know it's small, but it should enlarge when you click on it, I hope. Line 143 reads Jas. Mulvany, 25. Line 144 reads Bridget --, 22. Line 145 reads Thomas Mulvany, 16. And, most interestingly, line 146 reads Jas. Bothwell, 16.
There's not much information here, other than ages (which generally but not exactly match the ages James and Bridget provided census takers over the years). They tell us that all of these passengers are coming from Ireland, to the US. Unlike later ships' manifests, there's not detailed information about whence came the immigrants, who they were meeting and where, and their nearest relatives at home.
It would not be unusual for 16-year-old Thomas Mulvany to be the younger brother - or even, I suppose, a cousin - of James. After all, one of his sons was named Thomas.
But what I think is potentially most important - though also potentially a completely irrelevant coincidence - is the next name on the list, James Bothwell, which gives me a little more ammunition for the belief that this is, in fact, the correct record. Is this Bridget's younger brother? Is Bridget's real last name actually Bothwell? Is this a misspelling of Rothwell? It does give me a little additional evidence that the suffix of Bridget's maiden is -well, although it does potentially call into question the Roth- part.