Trollers Gill (Skyreholme Beck Valley), Skyreholme, Pateley Bridge District, North Pennines, North Yorkshire, England, UK

Trollers Gill is a collapsed limestone cavern at the head of the Skyreholme Beck. The gill itself is normally dry as the beck disappears into a sinkhole at its head in the Great Scar Limestone to re-emerge as a spring from its base at the foot of the gill. On the day I visited the beck was running through the gill also, and the volume of water issuing from the spring was sufficient to lift the turf of the footpath producing an interesting waterbed-like sensation.
Some weakly mineralised veins cross the valley, notably the Nape Well Vein and Old Man's Seam. At the head of the gill, there are some dumps, with very little mineralised material present, presumably from workings on the Pimley and Rodhill veins. Gill Heads Mine, described as a seperate locality, is in fact at the head of the dry valley to the west of Trollers Gill and separated from it by Middle Hill.
The grid reference given (in full SE 06637 61534 from GPS) is for an outcrop of veinlets in a steep rill where I believe the Nape Well Vein crosses the valley. I was able to collect some reasonable nail-head calcite from here, but there was no other mineral present.
Fluorite is present in the bed of the beck near the crossing of the last wall before the foot of the gill, as abundant rounded white to colourless pebbles. Whether this is the result of old workings higher up the valley remains unknown.
Specimens labelled 'Trollers Gill' probably come from Gillheads Mine.