I expect the stone wasn't big enought to hold any more calendar. They figured they had made enough calendar and when that one ran out they could make a new one!
I mean, do folks expect the Mayan calendar to go on for a billion years, or something? Gotta get tired of carving stone sooner or later!
I mean, do folks expect the Mayan calendar to go on for a billion years, or something? Gotta get tired of carving stone sooner or later!