section of underground river as far as The Junction, subsequently reaching the extent of Martel and Jameson's explorations. Bolstered by the experience, and the good possibility of further discoveries, the Yorkshire Ramblers returned in Easter 1908. A group of cavers descended a pothole located close to the large dolines on the plateau and discovered the Great Boulder Chamber. After a few hours of exploring, they realised that they had found a new route into Pool Chamber, bypassing the deep water of the original entrance. During the 1908 explorations, the Yorkshire Ramblers conducted tests to ascertain the hydrological connections between caves. They performed a dye tracing experiment with fluorescein, establishing a direct hydrological connection from the Aghinrawn River sink at Monastir cliff, via Upper Cradle Hole Cave (situated on the south side of Cradle Hole), to the Cladagh Glen resurgence. While surveying Lower Cradle Hole Cave, one caver sent a floating candle downstream along the river, until it floated under a low ceiling out of sight at the end of the known passage. On plotting the surveyed passage on a map alongside Marble Arch Cave, it was apparent that only separated the end of this passage from the upstream end of the Grand Gallery, and it was postulated that a connection between the two might be forged. 1935–1938: Skreen Hill and connections No further exploration was made until Easter 1935 when another group from the Yorkshire Ramblers' Club made their way from England. In wet conditions, the cavers re-entered Pool Chamber via the entrance found in 1908, and after some investigation discovered a high-level crawling passage exiting the chamber. The passage ended high in the wall of New Chamber, a cavern of considerable size, where the upstream continuation of the river was found. Exploration was halted here as the water was too deep to pass. The club returned to New Chamber in 1936 to explore and survey the ongoing Skreen Hill passage, named after the hill on the surface above. After of walking passage, the cavers stopped at a deep lake. This section of deep water is where the path of the current show cave ends. When club members returned again in 1938 they brought an inflatable dinghy, allowing them to progress across the lake, only to discover that the way on was blocked by Sump 1, just from the shore. During the 1935 expedition another group of cavers explored Lower