Thread: help with nail ID

first let me say I didn't know where to post this so if it needs to be shifted please do so.
The nail is triangular with a flat head, 2" in length and was only used to skew nail the jarrah joists to a jarrah plate. The nearest I can date it is 1880-1885.
I have tried google and am aware most nails came from Ewbank in England with some from America.
It is around the time of the manufacture of wire nails and am wondering if this shape is a precursor of the round wire nail.
The other cut nails were used to fix the baltic pine flooring.
So the question is where did this nail come from.