Are these just rocks ?

I found these on my daily walk . they looked odd so i picked them up . They are sandstone on the outside ,but on the inside you can see it is black/grey .they were all in the same are and broken up. sorry about the picture , the lighting wasn't that good .
The area I found them at is by the Arkansas River in Oklahoma.
my picture did not upload ,sorry everyone ,i am trying to get one on here

the rocks?this is the pic

Your pictures turned out a little small

thanks! sorry the picture turned out so small

The larger the picture size then the better we can see details. Most photo programs will allow you to resize with an edit feature. I use one called Nero which is simple and works fine. If not you can always use the paint program which also lets you resize the photo. I try and keep mine close to the limits set here like 2000 X 2000 pixels. Some cameras will let you set the size to enter your memory card.

here is a larger picturegrr lol never mind