Hi Trudy. Following up on Ross's suggestion, here are four pieces by Peter Goss with extensive trailing.
I don't think yours is in fact by Peter Goss. There are certain distinctive similarities, namely the square shape and the silver chloride (?) trails. Also you found it in Australia, where he lived and worked.
On the other hand, Peter Goss was careful to sign each piece, and every one I have seen with trails like this has extra decoration in the form of coloured chips rolled into the surface. Also the way the trails continue onto the base of your item is unusual and not at all like his handiwork.
Trevor