 The rushing waters of what would become known as Spruce Creek eroded a natural amphitheater at roughly 2,000 feet (609 m) on the south slope of South Mountain.Most of the drop is accounted for by the upper cascade.The shelf dividing the two falls (and creating the large pool between them) is the break between the Manorkill Sandstone formed in the Middle Devonian period and the Oneonta-Genesee sandstone-shale mixture of the late Devonian period.