[5] It is thought that what is now the main cave is relatively recent, and that some 350,000 years ago water sinking at Rumbling Hole followed a phreatic trunk route along the fault, entering Death's Head Hole at the end of East Passage, flowed across what is now the Main Chamber, into the passages below Big Meanie.

The main shaft of the hole represents the mouth; a bridgelike bar of rock passes across the eastern verge, but is hollow below, so as to connect the chasm with a more shallow cavity beyond.

The most peculiar feature, however, consists in a second bar-like bridge of limestone somewhat more slender than the first, spanning the secondary rift in exactly the opposite direction to that assumed by the former, so as to meet the greater bar in the middle of its course and form part of the same trellice bridgework.

[7]The first descent was by the Yorkshire Ramblers' Club in 1889, when they reached the bottom of the Main Chamber, and noted the stream entering from the east.

[8] In 1892 the cave was referred to as "Hell Hole" by the local historian and writer Harry Speight, who mistakenly reported that "the true bottom has never been reached".

[12] The connection with Long Drop Cave was made after bailing the short section of waterlogged passage, by the Gritstone Club in 1981.