A report on the big river caves of Papua New Guinea in the Nakanai Mountains and one on harvesting swiftlet nests in Sarawak by David Gill form a large part of this issue of Cave and Karst Science, along with reports on subjects as diverse as Northern Pennine maze caves and the hydrological significance of a Roman dog.

The issue opens on a melancholy note with a remembrance of three notable cave explorers and scientists who have recently died: Dave Checkley, Peter Standing and Chas Yonge. All three are sadly missed.

There are ten main articles in Volume 47 no. 1, starting with a report on caves in conglomerate in Greece. Georgios Lazaridis writes that Karst dissolution in the conglomerates of the Meteora area has previously escaped the attention of studies that deal with their formation and evolution as a landform. In this paper the presence of dissolution caves is reported and in particular the Drakospilia cave is presented in detail. Its morphology is indicative of a phreatic cave system that has shifted from the phreatic to the vadose zone.

Then comes the first of David Gill’s reports on the caves and karst of the West Iso River, Nakanai Mountains, East New Britain, Papua New Guinea. Beginning in 1984 as the Untamed River Expedition, the main area of exploration by British teams was the west Iso Valley. The Nare was explored to a conclusion along with other caves feeding the Nare River; the Pavia River Cave is the major inlet. A separate underground drainage system was mapped at Gamvo. Due to high cost and complex logistics it was 2006 before a return was made, with the National Geographic, to the Ora doline in a remote area at the head of the Iso River. The Ora system was explored to a conclusion and the major river inlet cave, Phantom Pot, was explored fully and mapped. During a helicopter flight a huge resurgence was noted issuing from the west cliffs of the Iso River. Mageni was explored and mapped but the cave continues beyond the farthest point reached. Some recommendations for future work are included.

Paul Taylor writes about dye tracing in the Slaughter and Ban-y-gor catchment areas of the Forest of Dean. A brief history of cave exploration and hydrological study in the area of the Slaughter Resurgence catchment during the past 60 years is presented, followed by an interim report of recent dye tracing in this catchment and in that of the Ban-y-gor Resurgence, further south in the Forest

Next comes the first of two papers on edible-nest swiftlets. Don McFarlane, Joyce Lundberg and Guy van Rentergem report on evidence for early human visits to, and possible edible-nest swiftlet exploitation of, Deer Cave, Sarawak, Western Borneo. They report a radiocarbon age of 2150 ±30 radiocarbon years before AD 1950 or 2305–2040 calendar years BP (94% probability) on human-sourced charcoal that they conjecture may be associated with an edible-nest swiftlet roost in Deer Cave, Gunung Mulu National Park, Sarawak. This is therefore amongst the earliest archaeological evidence of indigenous human exploitation of cave resources in the Mulu karst, and the earliest documented evidence of probable swiftlet exploitation in Southeast Asia.

The second paper is that by David Gill on the Middle Baram caves and karst areas, Sarawak. They are often referred to as the Gading Karst near Long Laput and have been known for more than 150 years as a source of the valuable, edible, nest of the White-nest Swiftlet (Aerodramus fuciphagus; also known as the Edible-nest Swiftlet). In recent years it has become apparent that outside of the Gomantong Caves in Sabah, the area contains the only viable colony of this rare swiftlet species to be found in Borneo. It was also known that extensive limestone quarrying in the region was destroying some caves and threatening many more.

Under licences issued by the Sarawak Forest Department, the local community, the Kayans, had been harvesting nests in more than 100 caves in 28 separate limestone areas, generating considerable income. Hence the karst and caves were considered as valuable assets. An appeal was made by the local community, stating that the caves were disappearing rapidly as the quarry area expanded. Over the years bird numbers had declined alarmingly, with less than an estimated 15,000 breeding pairs remaining. Survey of the limestones revealed that most of the Batu Gading limestone outcrop to the north and much of another eight outcrops had been destroyed, along with their caves and the swiftlets. Only six major areas remained. A cave and karst survey was undertaken and a sustainable nest-harvesting operation was introduced, with a significant positive effect. An attempt made by the author to have the karst scheduled as a National Park was unsuccessful. The history, geology, karst regions and the eight mapped caves are described.

Moving across to South Africa, Stephen Craven reports on the exploration history of Twinpot (otherwise known as Tripot) Western Province, from 1868 to the present day.

Chris Curry, Tony Harrison and Pete Roe write on the discovery and exploration of Danby Level Caverns and their morphology in relation to other large maze caves in the Northern Pennines, UK. Several complex and extensive maze caves, most only accessible from redundant mine workings, have been discovered in the area over the last few decades, and are known to have hypogenic origins. In early 2019 a further such system, Danby Level Caverns, was discovered in Arkengarthdale, North Yorkshire, and this has now been explored and surveyed. It has a surveyed plan length of 2.2km and differs in morphology from similar previously explored caves in having numerous low and wide passages (in contrast to the typical rift-shaped passages of other systems). This is thought to reflect locally anomalous aspects of the geology within a fault-bounded block of the Early Namurian (Pendleian) Great Limestone Member.

In a change of pace, Phil Murphy and Max Moseley describe the achievements and legacy of the Lancaster Cave and Mine Research Society. This society existed from 1967 to 1980. It focussed on speleological, archaeological and mining history research in the Morecambe Bay area. To support these activities the club developed a Field Research Centre at Warton Crag. After the demise of the club the field centre was no longer maintained and many artefacts and documents were lost. Currently legacies of the club’s publishing and recording activities continue to be important sources of information about the area.

Phil Murphy, this time with Andrew Chamberlain, also describes A Roman dog from Conistone Dib, Upper Wharfedale, UK, and its palaeohydrological significance. Dog bones recovered from the dry valley system of Conistone Dib have been radiocarbon-dated to the Roman period. The assemblage appears to have been emplaced by a flood event, suggesting that significant surface water flow in the now dry valley has occurred as recently as 2000 years ago.

The last of the main contributions to this issue is a report on the digitisation of the biological records of the Cave Research Group of Great Britain by Graham Proudlove and Will Burn. A fully digital version of the biological data collected in British and Irish caves between 1938 and 1976 is now available. It contains 5581 individual records and the original printed page for each record can be viewed as a pdf image.

The issue is rounded off with two short communications: a note on 100 Memories, an oral history of the University of Bristol Spelaeological Society in its centenary year by Nick Stromberg and, following up on a contribution to the previous issue, one on the puzzle of Frank i’ th’ Rocks Cave, Wolfscote Dale, Derbyshire, UK by Jenny Potts. Finally there is a comment and book review by Trevor Shaw of Wissenskulturen des Subterranen: Vermittler im Spannungsfeld zwischen Wissenschaft und Öffentlichkeit, Ein biografisches Lexikon by Johannes Mattes.

Cave and Karst Science is published three times a year and is free to paid-up members of the British Cave Research Association. Members can also read it online here. Non-members may obtain copies for an annual subscription of £40 (plus postage for non-UK destinations), or online access is only £30. A discounted student subscription is available. The publication contains a wealth of information and represents excellent value for money for anyone with an interest in the science of caves. It is well-presented throughout, with a clear, attractive layout and numerous high-quality illustrations..