One of a set of 4 holes within 10m or so of each other. This one is a narrow rift where a small hole has been enlarged and a pitch descended to 8m depth.
Other nearby holes are 4223, 4224, 4225.

Reference: anon., 2015d (autumn logbook)
Entrance picture : yes
Underground pictures :
Video :
Detailed survey :
Line Survey :
On area survey :
Survex file :