P. & S.R.R. on the obverse of an 1807 O-102 Draped Bust half dollar. cf. Brunk P-8, Rulau NH-Po 5. EF Details--Damage (PCGS).
Different from the cataloged type, perhaps this counterstamp is an abbreviation for Portland (or Portsmouth) and Saco Railroad? The unfair PCGS qualifier refers to the counterstamp.

Estimate: $400