In the link, if you click on the Town Called Pandemonium it takes you to another page that shows the authors of the ten stories and has a little more description of Pandemonium. Also says it's science fiction writers.
It sounds to me like the stories about the western town are already written or being written by the ten listed and they will include some more stories from 1853 placed outside North America. From their previous anthology, my guess is the number of other stories is 8. Puma