Projects

Overview

York Caving Club members are involved in several projects across the North York Moors, and occasionally further afield including the Northern Dales. We dig with members of the North York Moors Caving Club (NYMCC), and since the start of the collaboration between our two clubs we have discovered about 4 km of cave passage, mostly as part of the every-growing Excalibur Pot system, but also several other smaller discoveries elsewhere.

Our members, through work with NYMCC and the Cleveland Mining Heritage Society, have also been involved in the rediscovery and resurveying of several kilometres of abandoned mine passages, including jet, whinstone and ironstone.

Information on some of our projects, past and present, can be found in this section. This is just a selection of our most significant projects over the years, and for a more thorough record we recommend reading our journals.

The NYMCC website is a useful resource and includes fully digitised Moldywarps Speleo Group (MSG) journals dating back to the 1960s. The MSG were pioneers in discovering new caves in areas forgotten by many cavers, mostly the Northern Dales, but also the North York Moors too. The NYMCC website also contains their own newsletters (from when the club was called Scarborough Caving Club), cataloguing their work in the area during the 1980s-1990s, and reproduction of the cave descriptions and surveys found in Moorland Caver, a guidebook for the area published by Scarborough Caving Club members in 2003. This guidebook is out of print but can be purchased as an E-Book is desired.

We are actively researching, and re-writing Moorland Caver and we hope to published a fully updated edition of this in the next few years.

If you would like to know more, or would like to get involved, please contact us. We have regular digging meets, every Wednesday evening, and sometimes at weekends, usually ending up at The Crown Inn at Hutton-le-Hole. 

Introduction to Caves on the North York Moors

Across the southern end of the North York Moors, from Sutton Bank to Scarborough, is a band of Jurassic limestone. This limestone is younger and thinner than the carboniferous limestone of The Dales, having formed between 150-200 million years ago, yet still bears the potential to form extensive caves.

Despite the abundance of limestone, caves and potholes are not commonplace. This may be due to a combination of the geology of the limestone (typically only 30-50m thick, and often quite impure with less soluble calcareous grit bands) and the geography and hydrology of the local area, with few gritstone capped hills to channel water flow into distinct swallets as we see in The Yorkshire Dales.

The geography of the area is dominated by the past action of ice and sea levels. During the most recent ice ages (the last being around 20000 years ago), the North York Moors were bordered by thick ice sheets. As the ice melted, the only direction the water could escape was southward across the Moors, gouging out many of the valleys we see today across the limestone landscape. The Vale of Pickering (a low-level flat plain between the south end of the Moors and the start of the Wolds and Hambleton Hills) filled up, with water unable to escape due to ice barriers, and became an enormous lake. This eventually overflowed, cutting down the present-day valley of the River Derwent.

One of the most notable landmarks, Sutton Bank, and the Whitestone Cliffs on the west side of the Moors, were also formed by an enormous ice sheet that formed down Vale of Mowbray between the Moors and the Dales during this same glaciation event.

Clearly therefore, much more water once drained across the limestone band to the south of the Moors than does today. Subterranean drainage may have played a significant role in the hydrology of the area during these times.

Two main cave-forming bands of limestone are found in the area. The upper layer is the Malton Oolite, typically around 10-15m thick, and is surface-exposed in many areas. Many phreatic caves have been found in the Malton Oolite at Kirkdale, Boltby, Kirkbymoorside and Fadmoor. Kirkdale Cave was, until our discoveries in 2007, the longest water-formed cave in the area, with over 200m of passage. It may once have been much longer! The size of some of the phreatic passages in nearby Manor Vale Caves and Fadmoor Cave indicated a significant volume and flow of water at one point in these systems.

All of these caves became choked with mud which was deposited as flow rates reduced and silt washed into, rather than through the cave. The caves slowly become abandoned. Today, many of the caves have been left high and dry from modern-day streams that may once have entered them. Few now extend more than 50m into their potentially once extensive systems before encountering a solid mud blockage, and some are filled completely.

The second cave-forming limestone is the Hambleton Oolite, 30m thick and underlying the Malton Oolite, separated from it by the Middle Calcareous Grit. The Excalibur Pot/Jenga Pot cave system is found in the Hambleton Oolite, although Bogg Hall, the resurgence is in the Malton Oolite, with The Font, the resurgence pool in Bogg Hall Cave, being an underwater pothole that transitions between the two limestone bands.

Today, the most well-known caves in the area are slip-rifts (known locally as windypits), where land slippage near to steep sided valleys, particularly around the valley of the River Rye, has opened up a series of deep and lengthy fissures often extending for hundreds of metres. These are entertaining to explore, however many are off-limits for recreational cavers due to issues of land access and conservation, with many having been the site of important archaeological finds. Many, but not all, of the Windypits are found in the Hambleton Oolite, although they are not phreatically active.

In 1981, the belief that active caves (i.e. water-formed caves still carrying a stream) were absent from the North York Moors changed, when two divers from Scunthorpe Caving Club discovered Bogg Hall Cave in Keldholme after diving a resurgence in the River Dove.

Over the following 20 years, Scarborough Caving Club (who later became the North York Moors Caving Club) found many other small abandoned phreatic caves and new windypits in the area, leading to the publication of the first caving guidebook for the area, Moorland Caver, by Jerry Gibbs and Rick Stewart.

Despite the new guidebook, the North York Moors remained a speleo-backwater with little to tempt sporting cavers over from the neighbouring Yorkshire Dales.

In 2007, a few future members of York Caving Club took an interest in the area and its potential. We arranged permission to dig at the Hutton Beck sinks, a known feeder for the water in Bogg Hall Rising, one mile away. We were joined by members of Scarborough Caving Club (who were in a period or dormancy at he time) and within a few months we made the breakthrough into Excalibur Pot. Within five weeks of the discovery we had explored 1.8 km of new cave including a stunning main streamway carrying the entire subterranean course of Hutton Beck a fraction of its journey to Bogg Hall Rising.

The Hutton Beck area continued to yield further big discoveries, including Jenga Pot in 2013 further down the same valley, which was connected to Excalibur Pot in 2015. Then, further big discoveries beyond three sumps in Jenga Pot in 2020 brought the total system length beyond 3.5 km, with further big extensions still expected.

Since the Excalibur discovery, we have met one weekday evening each week (usually Wednesdays) to pursue various projects, and this has now become a staple part of the week for those involved. We now know that the North York Moors can harbour extensive active cave systems, and there is good reason to believe more exist. The search goes on for more, although the area doesn’t give up its secrets easily and clues are sparse.

If you would like to know more about cave exploration in the area, or if you would be interested in joining us one Wednesday evening (even if just for a chat at the pub after) then please contact us. Much of our work is covered by our journals, which can be purchased via our publications section and information on specific projects can be found here on our website.