We used to cross under a wooden railroad trestle to get to some land we were working on. I looked around the old wooden structure and found several spikes just like that. So it's a trestle or bridge spike.
That is making sense. There are a couple wooden railroad trestle bridges near by and the old wooden bridge missing really close by up stream from the 72 flood . I remember the road was closed most of the summer, there is a metal bridge where the old wooden bridge use to be.Thanks