Farthing 1850

I think it may be because early Victorian mintage figures recorded the number of coins of a particular denomination struck in that calendar year, not those bearing that year's date. Some 1849 dies may have been used into 1850, and 1851 dies could possibly have been brought into use before the end of the year. A classic example is the 1869 bronze penny, which has an official mintage figure of 2.6 million but is very scarce.