It could well be a Ross lens, they redesigned their WA Symmetrical towards the end of the 1890's so it would be 1897 or earlier, the G may well be the Agents//Company who sold the lens. I have seen a Ross Wide Angle Portable Symmetrical without the Ross name on it.

Rodd had links with Goerz and Ross making their lenses in the UK and for export to the British Empire.

Ian