1900 The Yorkshire Geological & Polytechnic Society (YGPS) traced Fell Beck water at Gaping Gill to Clapham Beck Head. Eldon Hole was descended by the Kyndwr Club, on their second attempt they used a bosun’s chair lowered through a pulley which itself ran on a cable stretched tightly across the shaft.
1901 Swildon’s Hole was first entered and explored as far as the top of the 40ft pitch. As part of their continuing programme of studies the YGPS dye tested Alum Pot to Footnaws Hole and Turn Dub. Eli Simpson made his first recorded caving trip, at Stump Cross Caverns. The Bottomless Pit in Speedwell Cavern was descended.
1902 Swildon’s Hole was closed by the Lord of the Manor who forbade any access. Work began to dig a way into Eastwater Cavern and in April the entrance boulder choke was passed and much of the cave explored. Major explorations took place in Peak Cavern and in Bagshawe Cavern.
1903 Eastwater Cavern was further explored by a combined group of Derbyshire, Mendip and Yorkshire cavers. The Yorkshire Ramblers Club (YRC) returned to Gaping Gill, Reginald Farrer descended into the Main Chamber and Booth-Parsons Crawl was discovered. The already known Old Roof Traverse in Lost John’s was pushed and the very wet Monastery Pitch descended by YRC members for the first time. Eli Simpson surveyed and photographed parts of Stump Cross. Mendip diggers started work on Hillgrove Swallet; although there have been some gaps digging is still in progress at this site. The West Series of Wookey Hole was explored by Balch.
1904 The first woman (Miss LE May Johnson) descended Gaping Gill with Leeds Ramblers Club. An attempt was made to use guidewires to stop the chair spinning but this was abandoned after one broke. Jockey Hole and Rift Pot were explored by YRC. Many small Chapel-le-Dale caves were surveyed by Yorkshire Speleological Association (YSA) members although the YSA was not formally founded until 1906.
1905 The YRC descended Gaping Gill main shaft on ladders and discovered T Junction and “The Great Hall” (later renamed Sand Cavern). YRC found a prehistoric skeleton in Scosca Cave. YRC reached the second pitch in Meregill Hole. EA Baker and friends pushed part way along the rift in Juniper Gulf, below the present-day traverse route.
1906 The Mendip Nature Research Club was formed, the first true caving club on Mendip (renamed Mendip Nature Research Committee in 1907). Despite the surveying work done in 1904 this year saw the first formal meet of the YSA; the first club to be formed for the express purpose of exploring caves. The YSA made the first descent of Hardrawkin Pot and followed Long Kin East Cave all the way to Rift Pot.
1907 YRC descended SE Pot in Gaping Gill to the water surface. The Netherworld of Mendip by EA Baker was published.
1908 Flood Entrance to Gaping Gill discovered, but SE Passage was not reached from this entrance until the following year. A YRC group were flooded in for over 6 hours in Long Churn. Another YRC group reached the third pitch of Meregill Hole. Rift Pot (Allotment) was bottomed.
1909 The YRC used a guidewire down Jib Tunnel to try and keep the GG chair out of the water. The entrance to Rat Hole was first spotted and the YRC made the first descent of Sunset Hole. The collapsed entrance to Oxlow Caverns was dug out by the Derbyshire Pennine Club.