What is this?

This is the second iron cover that I have noted in a sidewalk or driveway in a couple weeks. It definitely isn’t a water meter cover. Both homes were constructed in the early fifties. I was wondering if it might be a cover for a fill tube to a fuel tank? These homes didn’t have basements but rather crawlspaces and the furnaces in these places are fueled by natural gas now. Any answers?

Water valve cover,(buffalo box) ?

I use to work for a petroleum company, these types of covers are very common as monitoring well points, but its hard to say exactly what it is without it open.

It wouldn’t have been a water valve cover unless it pre-dated the water meter itself which is about 25 feet away. I hadn’t been opened in years so the bolt was jammed.