Wormhill Springs is one of the largest risings in the limestone area, with an estimated discharge of at least 10 mgd., and the catchment is probably the most promising area in the White Peak for an undiscovered large cave system.
The springs lie to the south of the axis of the Wormhill - Priestcliffe Syncline close to a fault parallel to the axis. To the north west the Upper and Lower Millers Dale Lavas have concentric outcrops, while between Great Rocks Dale and the shale margin extensive faulting gives rise to complex dolerite and lava outcrops. There is little evidence of high level cave development, suggesting that the Great Rocks Dale and Wormhill Springs have been the main outlets for a considerable period. Numerous small dolines exist on the margins of the lava outcrops, but none have been dug.
Apart from Cow Low Pot, the major swallets at Dove Holes have not been extensively dug, but have been dye tested to the impenetrable fissures in the Dove Holes railway tunnel. It has also been claimed (along with some very unlikely claims!) that they were tested many years ago to the Great Rocks Dale risings.
The driving of the railway tunnel effectively captured the drainage, sending it to the Irish Sea via the Mersey instead of to the North Sea via the Trent. The artificial lowering of water levels may have rendered more cave penetrable than would otherwise have been the case. Further digging should bring interesting results.
Wormhill Springs responds fast in flood conditions, and becomes milky in colour, suggesting that the catchment area includes the floors of the quarries in Great Rocks Dale. Rumours of a hole with a large stream flowing in it appearing in the quarry floor have not been substantiated but should not be entirely discounted. The drainage from Dove Holes must pass through faults in the Lower Millers Dale Lava to reach either the springs at Great Rocks Dale or the Wormhill risings. East-west faults may carry water eastwards to Great Rocks Dale, while faults further to the north carry water eastwards to join the Wormhill system.
Perched groundwater rises above the Upper Millers Dale Lava around Bole Hill and Withered Low, flows over both lavas, and sinks again. Digging at these small sinks may well prove worthwhile.
The existence of the flood-prone Wormhill springs, the swallets nearly four miles away at Dove Holes, the many dolines, and the favourable geological structure suggest the existence of a large cave system. The rising itself may be a deep one, but large vadose canyon passages could exist further upstream. Perhaps a JCB at Wormhill Springs could be the answer!