Fossil is the name given to the third main expansion of the Pokémon TCG. In Japan, it was released as Mystery of the Fossils. It is based on Pokémon Red, Blue, and Green, featuring Generation I Pokémon and Fossil Pokémon. The English expansion was released on October 10, 1999, while the Japanese expansion was released on June 21, 1997. It was originally planned to be released in the United States around January 2000 (based on initial Jungle estimates). However, since Jungle was released earlier, Fossil was pushed forward as well.