Waterworks

Millions of years ago plants and animals died and fell to be bottom of an inland sea, forming layers of limestone rock (some hard, some soft). In more modern times the River Hay has carved away a 130ft deep gorge, four miles long. Alexander Falls is a cap-rock falls, 103 feet high. The river flowing over the hard rock erodes the softer rock underneath. As more limestone is eroded the cap breaks off and tumbles into the canyon. Alexander Falls is it eroding southward at a rate of 4 inches a year.