 The gorge separates the high Mount Pamitinan on the north from the high Mount Binacayan on the south with the Wawa Dam and Marikina River running between them.Mounts Pamitinan and Binacayan are two limestone mountains formed around 20-25 million years ago during the Miocene epoch.They create a dramatic backdrop to the "Wawa" Dam, so named for its resemblance to a portal or "entrance" in the local Dumagat language.