Geronimo Jackson was a band that apparently existed in the 70s. While inside the Hatch in Season 2, Hurley comes across one of their albums (Magna Carta), and asks Charlie if he's heard of them. Charlie says he hasn't, even though he knows a lot about music.

Geronimo Jackson is also mentioned again in "Further Instructions" during Locke's flashback. When John first brings Eddie to the "farm" Eddie is wearing a Magna Carter t-shirt, which prompts Mike to inquire about Eddie's interest in Geronimo Jackson. Eddie then replies that he thinks they're alright, and that the t-shirt was one of his father's old shirts. Mike then replies that Eddie's father had excellent taste in music.

Some fans speculate that Mike is in fact one of the members of Geronimo Jackson.

Although the producers have insisted in podcasts and other sources that Geronimo Jackson is in fact a real band from the 70s. They do how ever say that it is extremely hard to come across their album.

Some fans, however, speculate that Geronimo Jackson is simply a fabrication by the Lost producers, saying that Geronimo & Jackson were the surnames of the
producers of the Disney animated movie "Alice in Wonderland" from 1951 and ABC is a Disney owned company.

_____________________________________________________________________