I have excavated variations of those..
Working old dumpsites in Trona,Ca it's practically all-Akro here. Have found so many since I first began digging in March of 2003 I keep having to buy new display cases. One marble of interest was dug at great depth from a strata I'd estimate pre-1920. It's a green clearie that glows like a searchlight under UV light. Websearched it,found one similar being sold on Ebay as an early Akro marble.