Good job!! I did see that notice when I was looking, but when I saw the surname as BURNIE I didn't actually read it through. It just goes to show that they were mucking up the classifieds even back then.
Now here is the weird thing - in the next couple of years the same memorial is listed under the surname of WALLACE. Perhaps Louisa was in a relationship with a man named WALLACE? Her death and burial were definitely registered as THOMAS. Something else to investigate

Did you also notice that it says she was the SECOND daughter of Charles? So who was the first? The unnamed female child was registered in 1871 AFTER Louisa who was born in 1869, so there must have been another unregistered daughter sometime before that.
I do wonder if this sister "E. DOWNING" is the eldest daughter herself, just because I did spot this marriage:
Marriage
Emu Bay
Tasmania
10 Oct 1879
Ellen Lavinia THOMAS
James Daniel John DOWNING
For this to be the marriage of one of Charles and Mary Ann's daughters she would have been born around 1864 at the latest, but probably earlier. Something else to be investigated further. I think she would have been living in WA when the notices were placed.
Debra
