The Bhumers and Cully's gang are going in opposite directions when they first meet; yet their paths cross again the same night.
When Jay Silverheels throws his knife into the calendar for June 1881, it shows June having 31 days. When he repeats the throw a few moments later, the hole made by the first throw has disappeared and June now has 30 days.
There is a calendar on the wall in the Sheriff's office that indicates 31 days but no month, although the calendar in Greasy's shop indicated the month as June.