Here's an interesting little article which might answer your question. Basically in the early days of the US, in this case 1874, local merchants made up the banking system in frontier towns, and often printed up their own money, or promissory notes.
Read on...
http://www.jstor.org/discover/10.23...=55910580493It's interesting to note that, if those are serial numbers in red on the left of your notes, the second one pictured is #1.
They're quite nice and seem to be in very good shape.