[drcoastline]

Originally Posted by fintstone

Flip it over.

It could be anything, but bollards are almost any size/shape imaginable as they are often purpose built. They are often anchored/set in (and sometimes filled with) mortar or welded down.

Yep, I know what a bollard is and that they come in many shapes and sizes. If you look at the OP photo again and read the description this thing is 12"x12" and weighs about 100lbs. Since Brian states it weighs about 100lbs., I would assume he lifted it off the ground. So whatever this thing is that is it.. There is nothing to sink into the ground. I don't see any holes so no way to fasten it to the ground. Note all the photos of bollards you posted have round tops and the OP photo shows a square. A bollard would not have a square as that could snag the eye in a line. The concave top would also allow a line to rest as opposed to side over.

I would not be surprised to see the underside hollowed out to fit over something like a post. The concave nature of the top also leans toward retaining something, like a person's neck, let their head hang over and whack or maybe a series of these in a row that you maybe would lay a rail on or a telephone pole or spar, so it won't roll while it is being worked on?.