Wyo. Stat. § 18-3-809: Treasurer to countersign and register all warrants.

When county orders or warrants are drawn by the county clerk and properly signed by the chairman of the board of county commissioners, before they are delivered to the person for whose benefit the same are drawn, they shall be presented by the clerk to the county treasurer who shall personally countersign the same and enter in a book kept by him for that purpose, the date, amount and number of each order or warrant, and the name of the person in whose favor the orders or warrants are drawn.