This site covers Yorkshire and the caving regions adjacent to this such as Cumbria and Lancashire.
The main caving area is in and adjacent to the Yorkshire Dales National Park, between Kirkby Lonsdale and Pateley Bridge.
Outlying areas include the fragmented blocks around Morecambe Bay, the Pennines north of the Yorkshire Dales National Park (Teesdale, Weardale, Alston) to Alston, Northumberland north of the Tyne, the North York Moors, and the Magnesian limestone caves which occur in a number of outcrops between County Durham and Derbyshire.

Selside, Ingleborough with Penyghent in the distance. Alum Pot is in the small coppice.

Geology

The tops of the mountains in the Pennines are formed from gritstone, below this is the Yoredale series, a repetitive sequence of limestone, shale and sandstone. Underneath this is the Great Scar limestone where many of the largest cave systems are found, and below this is a base of conglomerate rock.

The limestone sequence can be described by a variety of units, one of which is the biozone. Each biozone is characterised by certain fossils: D = Dibunophyllum, a solitary rugose coral; S = Seminula, a brachiopod; C = Caninia, a solitary rugose coral. They may be subdivided e.g. C2 and C1, the 2 being the upper (younger) of the two zones.

The limestone block presently reaches c. 500m altitude after repeated periods of erosion during the Pleistocene glaciations. Many of the famous landforms in the area were created at the end of the last glaciation (the Devensian) e.g. Malham Cove. The ice sheets, up to 1800m thick, extended from Scotland and the Lake District down to the Cheshire plains and down the east coast, across to Ireland and Scandinavia.

The Yorkshire Dales and the Askrigg Block
The limestone in the main caving area between Kirkby Lonsdale and Pateley Bridge sits on a bed of elevated rock, the Askrigg Block. This block may still be uplifting and creating earthquakes along the faults such as the magnitude 3.6 quake at Kirkby Malzeard in January 2011. This area is bounded to the east by the Dent fault, to the south by the Craven Fault, and to the north east by Nidderdale and Wensleydale.

The highest limestone beds are in the Yoredale series which is a repetitive sequence of darker, thinly bedded limestones, shales and sandstones. The lowest limestone beds in the Yoredale series (D2) contain the most fossils. Around Ingleborough the base of the Yoredale series is a thick shale band and so here this series contains no caves, but further east the Yoredale series does contain some thicker bands of limestone that produce some more significant caves e.g. east of the River Wharf: Goyden Pot, Mossdale Caverns and part of Langcliffe. The water here manages to pass through beds of calcareous sandstone to reach the resurgence at Black Keld.

Beneath the Yoredale series is the Great Scar limestone and nearly all the major cave systems of the north-west are formed in this massive limestone. This limestone is mainly a fine-ground bioclastic limestone composed of c.50% fine calcite mud (micrite) or coarser sparry calcite (sparite), the other 50% being made up of fragments of organisms such as foramifera, shells and crinoids.

There are some significant bands running through the limestone - near the top of the Great Scar limestone is the Girvanella band, a 1m thick, dark grey bituminous limestone band containing nodules of algal fossils. The upper part of the Great Scar limestone (D1) is a pale grey/cream, fine grained, bioclastic limestone.
The Porcellaneous band (fine, white, micrite with very little sparite, c.70cm thick) divides D1 above and S2 below and is visible in the main chamber Gaping Ghyll. Beneath the Porcellaneous band the limestone is darker (S2), with the lowest S1 and C2 beds containing shales. The lower C2 limestone is oolitic limestone.
There are about twenty, unfossiliferous, mudstone shale bands that run through the limestone, these are up to 2m thick in e.g. Shale Cavern, Lost Johns. In places coal has formed on the top of the shale e.g. Coal Passage in Short Drop, Four Ways Chamber in Notts Pot.

Along the Craven faults to the south of the Yorkshire Dales National Park are Reef Knolls (e.g. Elbolton and Thorpe Kail Hills), consisting of porcellanous limestone with an abundance of fossil brachiopods, gastropods and lamellibranches.
In the Greenhow area the Stump Cross Caverns and Mongo Gill Hole are formed in an anticline.

The thickest areas of limestone is between Long Kin West and Moses Well (c.250m) due to faulting, and Black Keld in Wharfedale (230m thick) due to a thicker C2 base and the Great Scar limestone continuing up into the Hardrawkin limestone (part of the Yoredale series) without a break.

The dip of the limestone beds is a few degrees to the north-east with minor variations due to folding. Exceptions are close to the large faults e.g. Barbondale where it is tipped vertically against the Dent Fault, and 45 near the Craven Faults. Vadose cave passages generally flow in this north-east direction following the dip, before trending south-west in phreatic passages to the resurgence. The Kingsdale system is a classic example of this.

There are caves across this region and they include the longest cave system in the UK, the Three Counties System based around Easegill which has over 100km of passages. Gaping Ghyll is a famous cave on Ingleborough with an impressive 100m waterfall falling into a huge underground chamber. There are many popular group caves in the region including Yordas Pot and Valley Entrance in Kingsdale, Great Douk and Sunset Hole in Chapel le dale, the Ribblehead Caves, Long Churn, Old Ing, Browgill, Birkwith, Calf Holes and Old Ing in the Ribble valley, and Dow Cave and Goyden Pot in the east.

Pennines north of Swaledale and The Alston block
To the north of the Askrigg block lies the Alston block. Most of the caves in Weardale, Teesdale and around Alston are in the Great Limestone, a band approximately 20m thick that has a significant amount of mineralisation. This band of limestone is the equivalent of the Main Limestone at the top of the Yoredale series. There are many mine workings in this region and many mine workings and caves intersect.
There are many rarely visited caves but few are extensive. Two of the longest are Knock Fell Caverns and Fairy Holes, Weardale.

Morecambe Bay
The limestones around Morecambe bay are divided by north/south faults into a series of isolated limestone blocks, the local dip to the east is as much as 45 and each block has different characteristics. At Hutton Roof the dip on the limestone has allowed 15m long runnels to form. The limestone blocks of Morecambe Bay are formed from massive micritic and sparry limestones. Their elevation is up to 300m and they have been exposed for much longer than the Great Scar limestone. Generally there are no covering rocks and many caves will have been eroded away, the majority of the remaining caves are found in the Urswick Limestone, the equivalent to the Great Scar Limestone. These caves are short, close to the surface, do not have large streams and are relatively warm due to their low elevation. There is a variety of habitats around the caves including woodland and as a result there is wide variety of species recorded from these caves, including many that are not found further inland in the Great Scar limestone.
This area has not received the same attention as that further east and so there are many uncertainties about the geological history.

North York Moors
The dip here is to the south. The rocks are Jurassic and the caves are in Corallian limestone. This limestone is younger than the Great Scar limestone.

Limestone pavements
The Yorkshire Dales has the best examples of limestone pavement in Britain. Sparry limestones form massive beds with a lower frequency of bedding planes and joints. They have fewer weaknesses so the water that does its way underground in these beds tends to stay in those weaknesses, producing cave passages with high vertical walls. The pavements formed in sparry limestone tend to be comprised of large clints (the blocks) and deep grykes (to 3m). Those on Scales Moor and Scar Close have some rare flora associated with the grykes.

Micrites and biomicrites form less massive beds, with more prominent bedding planes and joints. Biomicrite pavements tend to flake and the grykes are shallower than those in sparry limestone. Biomicrite limestone has a relatively high porosity of 8% and tends to erode faster than pure micrite and sparite which has a porosity of 2-3%.
Acidic plant debris in the bottom of the grykes may increase the rate of erosion.

Limestone pavement beneath Ingleborough Southerscales Nature Reserve, Chapel le Dale.

Ice Ages
During the last ice (the Devensian, that ended around 10 000 years ago) northern England was glaciated, and although conditions were still very cold, sub-glacial tundra was present, similar to modern day Siberia.  Much of the life eked out a precarious existence or moved to warmer climes via the land bridge that still linked the south-eastern part of England to the near continent. It is possible that some organisms survived the Ice Age by living deep underground where the temperature was above freezing, but food would have been a major difficulty. Organisms that survive underground for generations will often have adaptations to help them survive, and will lose some features that are of no benefit e.g. use of eyes. Those that were or became adapted to life underground became troglobites - cave dwellers that complete their life cycle in the cave and do not exist outside of this environment. These are the most fascinating creatures you will see underground, but they are also part of a delicate ecosystem that is easily disturbed by cavers and man’s activities.