Hi accam,
I have checked the Pioneer index for Tasmania and can only find a marraige for a Christina Kerr to a John Williams.
5/06/1858 reg number 515/1858 Launceston RDG 37.
I found a birth for a Male child born 20/09/1856 reg number 857/1856 Launceston RDG 33.
Parents were Charles Merion and Christiana Kerr.
There are no other Merion surnames on the Indexes.
Johngirl.