Q. David Bowers (edited and updated by Mike Sherman): The Liberty Seated half dollar style of 1854-1855 with arrows at date is the same as used in 1853 except that the reverse rays have been deleted. Thus, the 1854-55 halves stand as a distinct type. Coinage was produced primarily at Philadelphia and New Orleans. In 1855 the San Francisco Mint issued the denomination for the first time, striking 129,950 pieces. This remains the only rare mintmark variety in the date span. An interesting variation is provided by the 1855/4 overdate, a variety which exists in business strike form as well as proof.
Like the 1853 arrows and rays type, examples are readily available in all grades from Good to About Uncirculated. Uncirculated pieces are naturally scarce, but not as scarce as the “with rays” variety.
-- Reprinted with permission from "United States Coins by Design Types - An Action Guide for the Collector and Investor" by Q. David Bowers