What is this?

[Eric O.]

[TheGoblinKing]

From the pictures, I'd have to say concrete. However, it's hard to get any sense of detail without any sunlight.

[Rockwood]

Masons commonly use rocks to help fill larger castings. It looks as if one may have reused some chunks of concrete as a filler here. It is hard to tell for sure though.

[Eric O.]

Sorry,  I should have given more info. This was believed to be a piece of railroad tie.when I first bought the house 7yrs ago. The grey on top is paint

[CrazyRockLady]

You may have a crypted on your hands since the first pic looks like something came along took a bite out of that thing lol.

                           

    

[Rockwood]

1 hour ago, Eric O. said:

Sorry,  I should have given more info. This was believed to be a piece of railroad tie.when I first bought the house 7yrs ago. The grey on top is paint

I wouldn't doubt that it could be a railroad tie. Concrete ones have surely been in use that long. The inclusion could well have shortened this ones time.

[JohnJ]

@Eric O.

 

Try taking well focused photos in natural light.