red datestamp with letters very close to the rim on 1849 folded letter to Philadelphia, matching cog "10", small nick along top edge, very fine strikes, the earliest recorded use of postmark A-4a, this postmark was first reported by Leonard Hartmann in the 1960s and was only used for two months in late-1849 and early-1850, letter written by J.B.F. Russell of the General Land Agency