Littondale is a side dale to the west of Wharfedale and follows the River Skirfare. The nature of the dale and its characteristic smooth form was the result of many ice ages, especially the one 20,000 years ago. As the glacier for that age receded it left retreat moraine, an example of which can be found at Skirfare Bridge. Like neighbouring Wharfedale, Littondale comprises mainly Great Scar Limestone and Yoredale rock. The dale has a number of shake holes and sink-holes that lead to cave systems such as at Boreham Cave. At the head of the dale is Pen-y-ghent, one of the Yorkshire Three Peaks.