Struck at the Chihuahua Mint (Ca mint mark), assayer RG.
Certified by NGC to XF 45, Population Census: this coin, only 2 higher (AU58, MS63).
Conditionally Rare!
All known examples are overdate: 1851/41.
Dunigan Ca22: "Very scarce and a very underrated date. With the exception of the extremely rare 1856 JC and 1858 BA, this date is the scarcest in the 1850s. There is no question that the 1851 is more difficult to find than the 1852 and 1853. It is also scarcer than any dates of the 1841-1849 period. Generally found in Very Fine condition. High grade examples are quite rare".