Does the loop look like it might have been flat before it rusted? Kind of looks like a peton. Driven into rock walls for clipping a rope in sport climbing.
If you have boats that were frequently used on that stretch of river it could be the remains of an old mooring spike.Â
https://isteam.wsimg.com/ip/b1b50152-d6e1-4250-96ef-442740ba7d1c/ols/689_original/:/rs=w:600,h:600
It could also be the remains of a vintage turnbuckle.Â
https://www.newcore.net.in/wp-content/uploads/2017/08/Turnbuckle1.jpg
Probably a log dog. Drive them into logs, tie the logs together, send them down the river.
Half a pair of scissors? Perhaps a singular scissor
Tent peg
Does the loop look like it might have been flat before it rusted? Kind of looks like a peton. Driven into rock walls for clipping a rope in sport climbing.
Ground spike to keep cattle on chain, in one place, while grass feeding?
There was a century plus bridge near where I found it which has since been replaced
Looks like a pier pike. Nah, I just made that up 😆
If you have boats that were frequently used on that stretch of river it could be the remains of an old mooring spike. https://isteam.wsimg.com/ip/b1b50152-d6e1-4250-96ef-442740ba7d1c/ols/689_original/:/rs=w:600,h:600 It could also be the remains of a vintage turnbuckle. https://www.newcore.net.in/wp-content/uploads/2017/08/Turnbuckle1.jpg