Sometimes one small piece of information can open up a multitude of possible links to follow. I've just purchased a transcript of the death certificate for John Mason in Adelaide in 1857. It gives me three new pieces of information that I didn't know before: he was a labourer, he died of 'disease of the heart', and the Informant for the registration was a Michael Murnane.
This intrigued me - who was Michael Murnane? I found two Michael Murnanes mentioned in the Adelaide newspapers around this time, a father and son, but I couldn't find any connection with the Masons, and neither seemed to hold any sort of official post that might be the reason for signing the certificate. A Michael Murnane arrived in South Australia in 1848 and the older Michael died in 1868 aged about 80.
A search on Google led me to a family history website which said that Michael Murnane had arrived in NSW from Ireland in 1837 on board the Lady McNaughton (or McNaghton). The passenger list for the Lady McNaghton (in the NSW State Records) showed that along with Michael Murnane and his family the passengers included a Catherine Murphy, aged 21.
Co-incidence? Possibly. It's likely that almost any ship carrying passengers from Ireland would include a Catherine Murphy. The name Michael Murnane seems to occur less frequently, and I've found two other family history sites that connect the 1837 arrival with the Adelaide Murnanes, so I'm more confident that this is the same family. Perhaps, since the Murnane's owned land in South Australia, they employed John Mason and that is the connection.
The other problem is Catherine's age, which is given as 21 in 1837. (Her age at death would suggest a birth about 1822). But it's quite possible that this is a 'rounded' figure, if she was travelling as a single woman.
The Lady McNaughton was famous (or notorious) for two things - it carried many single women looking for marriage, and an outbreak of typhus on the journey led to the deaths of over 60 passengers and to the ship being quarantined for weeks on its arrival in Sydney. But that's another story.
UPDATE: see Not the right Catherine after all