The flying eagle cent of 1855 with the reverse with 4 leaves under the 'E' in 'States'.
These were apparently struck early in 1855 as per the notation below which probably refers to J172/P198 from the Eckfeldt journal.
"Flying eagle cent struck in Feb 1855, the diameter 1 inch the tail a little small in the wreath; other ways (sic otherwise) the same as those of 1854".
Examples were struck as follows:
Copper/Bronze J167 & J168/P193. Both originals and restrikes are known and are extremely rare showing any red color.
Oroide J169/P194 with only a single example confirmed so far which was found to be 81% Copper, 15% Tin and 4% Zinc. Metallurgical analysis is recommended.
Copper-nickel 90% copper and 10% nickel J170A/P195 with about a dozen known, see note below.
Copper-nickel 80% copper and 20% nickel J170/P196 - see note below.
Copper-nickel 60% copper and 40% nickel J171/P196 - see note below.
German Silver J171A/P196 with about a dozen known. Pollock lists one on a 75% copper, 12% nickel and 13% zinc planchet and another on a 64% copper, 19% nickel and 17% zinc planchet was in ANR's 1/04 sale.
Pure Nickel J167A/P197. The Judd book mentions a Very Good example formerly offered by New England Rare Coin Galleries. This has not been available for study.
Note: These tend to be weakly struck. Metallurgical analysis is recommended with regard to any purported nickel alloy piece. Extensive testing by Rick Kay has shown that most, if not all, pieces described as J170 and J171 have turned out to be J170A or J171A.
Some of these were struck from sharply clashed dies including the J170/P196 in Ira and Larry Goldberg's Coins and Collectibles June 2000 sale. One would suspect the German silver coins to be originals as the experiments using German silver occurred from 1853-1855. If this is the case, then all restrikes should show some evidence of these clashed dies.
Eckfeldt journal image courtesy of Alan Meghrig.