This area lies to the south of the Castleton catchment area. It's a big area but as yet the theoretical "master cave" has yet to be discovered. The swallets are all choked and have thwarted all attempts of finding a feeder into the system. The main rising for the area is the highly significant Bagshawe Resurgence which produces more water than Castleton's Peak Cavern and Speedwell Cavern combined! Until recently this could only be explored for a few metres by diving to a point where it was blocked by a significant underwater boulder choke. Divers dug their way through it into a series of low and awkward submerged passages connecting to the downstream end of Bagshawe Cavern. Bagshawe is extensive with many ongoing leads, but again no way onto the "main drain" has been found. The area is also home to some significant 18th and 19th century lead mines which can still be explored.