The English version of Fossil was originally planned to be released around January 2000 (based on original Jungle estimates). But because Jungle was pushed ahead, Fossil was pushed ahead as well.
Wizards of the Coast once again increased the set size by producing holographic and non-holographic versions of the rare cards; however, they removed the Mew card that was in the Japanese set. Mew would later reappear as Wizards Black Star Promos #8 (non-holographic) and #9 (holographic).
Fossil completed the transition of the first 150 Pokémon (151 in Japan with the inclusion of Mew, whereas Mew would be a promo card in the English version) to card form. Base Set, Jungle and Fossil totaled 158 Pokémon, meaning 8 Pokémon were present in two expansions : Pikachu and Electrode were both in Bast Set and in Jungle, while Gastly, Haunter, Magmar, Magneton, Raichu and Zapdos appeared both in Base Set and in Fossil.
The Prerelease card for this set is Aerodactyl. It also happens to have the 1st Edition symbol on it.