@akroorka @Melissa Nice examples, Art, thanks for showing them. I'm sticking with something other than Akro for the OP - too many ribbon ends and the colors look very different to me. Maybe different Akro examples would convince me otherwise, but there are a few things about this marble that make me think Vacor too.
@Melissa Yes, bifurcated is when there are two distinctly different base glasses on opposite halves of the marble. In your marble, the light brown/tan color on the one side of the marble is produced by color "leaking out" from and between the two darker ribbons that border the area. I think the base is off for a Copperhead and the striping pattern doesn't look right to earn a Wood designation either, IMO.
The blue one is interesting, it looks a bit closer to a "transitional" to me - sort of unusual cut-off, IMO. In addition, I'm not sure I see facets on either - the second looks like a ground pontil?
As always, hoping to learn something here.
Just wanted to let you know. And thanks for editing your post. Lots of people consult these named threads and those in Steph's Study Hall looking for examples, it's nice to keep them "clean" so as not to mislead people.
They may all be Akro but 4 & 6 may deserve another view or two. If there is a visible cut-off it helps to see a straight-on shot of it and then pics of both sides (like you're showing in the last photo.
Gotta remember, Vacor made swirls for a very long time, and we don't know a lot about their production prior to the time they started naming them. Regardless, that kind of orange peel is uncommon, maybe even rare, on American marbles.
Wouldn't it be great if we could ID every marble? My guesses: Alley, Champion, Alley, Alley. It doesn't much matter though, the collectible and monetary value is minimal regardless of who made them.