Twincerely - I would agree that those are some XL game stones. The smooth one looks like a marble material and the rougher one may be limestone. Over time and if in contact with water the limestone can morph to into what is shown in the pictures where it is rouch and dimpled. On a side note I have also seen some flint nodes that look similar to the rough one that were pretty round, rough and heavy. I mention the heavy part only because early on when I started this adventure I toted those dadgum things thinking that I had something only to find out that I did not...lol!
Great finds....