Q. David Bowers (edited and updated by Mike Sherman): The Liberty Seated quarter with arrows at date and rays on the reverse design was modified in 1854 by dropping the rays but retaining the obverse arrows. Otherwise the type is essentially the same as produced from 1838 to early 1853. Coinage was effected at the Philadelphia, New Orleans and San Francisco mints, the latter beginning production in 1855. The most plentiful of the two dates is 1854, of which 12,380,000 were produced. A variety of 1854-O with a “huge O” mintmark is rare.
-- Reprinted with permission from "United States Coins by Design Types - An Action Guide for the Collector and Investor" by Q. David Bowers