✅ SOLVED Random patterns on an old rock or markings?

[deldave]

This size rock is way out of place in our farm fields here in Delaware. It was covered with mud when I picked it up but I was curious so I brought it home. I have never seen this many marks on a field stone before and it fits my hand very well. As a novice I would appreciate all thoughts or opinion. Thanks ,deldave

 

[Flip N. Rocks]

It seems those marks are on one side? The top side? Probably plow marks. Worth looking into I wouldn’t toss it.