Marley is the dog belonging to George. He is the reason why George and Jane Vaughn met in New York City.
In Degrassi Takes Manhattan (2), George and Marley are playing in Central Park. Marley runs to Jane, who happens to be walking by. George runs after his dog, and apologizes for Marley's behavior to Jane. The two begin to talk and set up an audition for Jane for George's Band, Flashing Midnight.