Waterfalls form in three basic ways. They commonly develop where a hard, resistant streambed meets a softer one, because water erodes the softer layers faster and creates an abrupt, nearly vertical drop; Victoria and Niagra Falls are famous examples. They also form at hanging valleys, where a river cuts the main channel faster than smaller side channels and leaves a ledge where they meet, as seen at Multnomah Falls in Oregon and Yosemite Falls in California. A third way occurs when shifts or faults in the earth’s crust create steep ledges that rivers flow over, and Shell Falls is a prime example of this type.