From Bulbapedia, the community-driven Pokémon encyclopedia.
Sayda Island (Japanese: サイダ島 Sayda Island) is an anime-exclusive location in Kanto. It is home to Sayda Lab.
Sayda Island is a heavily forested area, with a rocky, mountainous portion that is notable for being where Crystal found the Fossilized Aerodactyl Egg. This Egg, along with a sample of Old Amber, was used by Gary and Crystal's sister, Dora, to revive an Aerodactyl, which broke free of the lab.
Sayda Island also has fruit trees, the fruit of which Aerodactyl has been depicted to enjoy eating.
Pokémon seen on Sayda Island