Lamb Leer Cavern in the Mendip Hills near West Harptree was discovered by miners in 1676 and was explored by John Beaumont, however the entrance shaft was lost some years later. This paper gives particulars of the people and events connected with the re-discovery of the cave in June 1880, by the miner Andrew Lyons, and its exploration in the next decade. Also examined are Lyons’ claims, made in 1937, that he came across a lake in a passage off the Great Chamber, and that a talking machine, presumably some kind of telephone, had been used there. Secondary evidence is introduced which suggests that the lake was a temporary feature formed during heavy rainfall. It is also shown that the mining personalities connected with the cave at that time, would have been aware of the development of the telephone and its use in mines. It is argued that an electric or mechanical telephone was used in the cave after its re-discovery and before February 1885, making this the earliest recorded use of a telephone in cave exploration anywhere in the world.