Hi Nancy, What is the size of the larger marble ? From the looks of it it may be a limestone is it heavy or very light ? A quick way to find out for sure is to put some type of acid on it or vineger it will react with bubbling and vapor if it is a limestone. The other one is a benny for sure and a late one at that.......Greg
Clam, the big one measures almost an inch in diameter and weighs about an ounce. I tried the vinegar test and nothing happened, so I guess it's clay. Not sure what you mean by "late" on the bennington. I posted another pic of it. Thank you for helping me with them.