Although there are many well-known caves and potholes on the Leck Fell side of Ease Gill, the only naturally open pots of any size on Casterton Fell are Cow Pot and Bull Pot of the Witches. Neither the original explorers of these holes, nor Fairbanks, Greenwood and Simpson who subsequently worked in Upper Ease Gill in the 'thirties ever succeeded in reaching the main underground drainage system. Eventually R.W.Taylor, G.Cornes, W.Oakes and Wilf Taylor, from Lancaster, members of the British Speleological Association, discovered Lancaster Hole (September 29th, 1946). With their club friends they soon forced a way down to the Ease Gill Master Cave. Oxford Pot in Upper Ease Gill, dug out by the same group on March 30th, 1947 and again by Simpson, Rawdin and the Gilberts on May 25th and 26th, and first explored on June 12th, appeared to be a feeder to this system, an idea which received further support in 1948 when 'unofficial' high level exploration from Lancaster Hole by B.S.A. members led through caverns of unprecedented quality to a fine water-passage gradually converging upon Upper Ease Gill to the north of Boundary Pot.
It should be said that, by this time, the B.S.A. had put a steel lid over Lancaster Hole and had obtained a leasehold over the nearby moor in order to control entry to the caverns beneath. The exact terms of this lease have never been made public, but it is believed that only 'authorised' members of the B.S.A. may legally go down, members of all other clubs being barred from entry. For some reason, the B.S.A. did not authorise the discoverers of the Far Reaches of Lancaster Hole to make many more trips into their Promised Land, and indeed, from this time on allowed fewer and fewer parties to go down the hole. When, in August 1950, a great mass of stone and concrete was dumped down over the only convenient entrance so that no-one could readily get in, members of other clubs felt themselves at liberty to tackle the unsolved problems of Upper Ease Gill. With the kind permission of the landowner, they began their investigations in an area into which, as far as was known, the B.S.A.'s leasehold rights did not extend.