Mineral deposits are commonly associated with geological structures. When mineral-rich fluids circulate deep underground, their dissolved minerals may crystallize within faults, fractures and joints, forming mineral veins. The Westmorland Dales contains very few mineral deposits, unlike other parts of the Yorkshire Dales and the neighbouring Lake District and North Pennines.
However, there are a few minor mineral veins and evidence of small-scale exploratory workings, probably dating mainly from the 19th century. At Great Bell near Nateby there are workings along two veins which were reported to contain small amounts of galena (lead ore) and fluorite. On Asby Winderwath Common, small excavations and an adit date from an attempt to work a small copper ore deposit in 1829. These deposits may represent outlying deposits of the mineralized areas of Mallerstang and Swaledale (part of the southern segment of the Northern Pennine Orefield).
Exploratory lead workings on Great Bell south of Nateby, looking west into the Westmorland Dales. © E. Pickett
Small adit on Asby Winderwath Common, a relic of small-scale copper mining around 1829. © E. Pickett