The Upper City is the Pre-level where Vince Delivers the Cloth of the ballon to Professor Ethel and a great place for vince to practice his jumping by collectting the skull pages. Vince Has to get to the top and ride a pail to the professor's place.
This level contains twenty-five Zombie Dust Bags, fifty skull pages and one heart at the topmost floor on the end of a wide pipe.
The Skull will spawn on the bottom level after collecting the final twenty five pages on the massive jumping-and-hovering pattern from the top floor to the bottom, which means Vince will be very close to it. The skull will travel from the first floor to the metal platform right off the third floor. It's best to anhillate the enemies before activating it because Vince won't have any problem getting it once the enemies are gone.