Between Cold Pike and Pike of Blisco is a wide grassy depression at 528 m (1,740 ft). On the southern side is the source of the River Duddon, while to the north is Red Tarn, a feeder of Great Langdale Beck. Red Tarn is an elongated pool whose stony bed can be seen through clear shallow waters, reputed to hold trout. Its name comes from the colour of the surrounding soil rather than the water itself. The tarn forms a focal point for walkers, as the wide path from the summit of Wrynose Pass to Great Langdale runs beside it, with a further path branching off across its outflow towards Crinkle Crags. The main path was originally made to serve Red Crag Mine, which now consists of a series of pits and trial borings for iron ore, concentrated about 300 metres north of the tarn. The mine was worked from 1860 to 1875 but never achieved commercial success.