Apart from the being the only one plus the geocachers, as we have completed the exploration and will be writing it up thought i would say more. 1800 yds long quoted and lies near Taunton. Taunton end negotiable for 800 metres with dinghy or such like useful/essential especially at far end. Dangerous in places, very well decorated with dig potential at terminal collapse, as estimated 500 metres still inaccessible, and would make a great through trip. Further info contact me via a PM.