The bonds shall be signed by the chairman of the board of county commissioners and attested by the county clerk and recorder and bear the seal of the county upon each bond and shall be numbered and registered in a book kept for that purpose in the order in which they are issued. Each bond shall state upon its face the amount for which the same is issued, to whom issued, and the date of its issuance; but no bond shall be of a lesser denomination than fifty dollars, and, if issued for a greater amount, for some multiple of that sum; and the aggregate amount of such bonds issued shall not exceed the sum entered of record by the board of county commissioners, and any bond issued in excess of said sum shall be null and void.
C.R.S. § 30-26-304