Picked up a large collection of marbles from a man in his 70's saying that these were his fathers. I noticed some have pontil marks (I think they are), but are not the typical german swirl. I also think some are Akro, Christensen among other American companies. I've noticed that most pontil mark examples have a melted on frosted mark. Most of these have a circular mark with a tiny nub in the middle. Any help would be greatly appreciated. Thank you all!!!