For two miles above the village of Gilsland the River Irthing flows through the Irthing Gorge, flanked by mainly sandstone crags. Within the upper section of this gorge, 3km from Gilsland, lies the spectacular 7.6 metre (25 feet) Crammel Linn waterfall. Peregrine falcons and ravens nest near the waterfall and derelict military structures, probably pump-houses supplying water for the Blue Streak rocket site at RAF Spadeadam, can be seen just upstream. Further downstream, in the grounds of Gilsland Spa hotel, the crags develop into high cliffs. The cliff face below the hotel gives rise to the famous sulphurous spring after which the hotel is named and also a chalybeate spring and a petrifying seep.
See more on Crammel Linn at Wikipedia.