Isla Sorna is the main setting of Jurassic Park: The Lost World and Jurassic Park 3, and the dinosaurs seen here and not in the first movie, such as the Spinosaurus, have not yet been brought to Jurassic Park, due to the park's disastrous failure.
Site B refers to Isla Sorna, where INGEN raise their dinosaurs before being sent to Jurassic Park to be displayed. You can choose your 5 (3 on PlayStation 2) dig sites upon starting, and the dinos related to these sites automatically have 100% DNA genome, so they can live longer. You have the ability to create dinosaurs and, rather than keeping them on display, let them roam free in a more natural way. In Site B there is no particular objective. However, you cannot place any buildings apart from hatcheries, lures and feeders.
Site B is an alternative gamemode where you have unlimited funds. You can pick up to five Fossil hunting sites, and when you pick your sites you have 100% DNA of all dinosaurs in the dig sites you have chosen.
