The morphology and deposits of Rhino Rift are described. The cave is an ‘invasion vadose cave’ formed when local saturation level was 75-90 m OD. Ten U-series dates on four speleothems show that a boulder and cobble infill at the bottom of the known cave accumulated sometime after c. 45,000 years ago, whereas poorly sorted muddy gravels blocking the entrance passage were laid down before c. 11,000 years ago. The cave itself was formed before 75,000 years ago, probably during Isotope Stages 5 or 6. The implications for the geomorphic history of the Mendip region are discussed.