A very much overused system providing several routes through classic Mendip streamways. The entrance series is prone to change, in as much as it looks different every time due to flooding opening up new routes. Old muddied formations are prominent in the upper streamway. There are, in total, 12 sumps in the main streamway with a round trip passing through four ducks, a muddy duck/sump and the first main streamway sump. Side passages around here provide ways to passages between some of the sumps allowing a through trip from Priddy Green Sink via Cowsh(*t) Avens. Several of the main stream sumps can be free dived but it is best to follow these with the help of a guide. The first sump was the site of the first cave dive attempt in Britain, in 1934, although the sump was not successfully passed until two years later.