United States Notes were discontinued in 1971...the last bit of "lawful money" pursuant to clubhouse rules left. But they are still listed in the USC and are represented by FRNs.
Printed copy · Anthology Volume 9, page 1164Printed copy from The Tender For Law Anthology, Volume 9, page 1164 (printed 13 June 2014). Added by this site; not part of the Facebook export.