Grid Ref. 92944429

Depth: 25m Length: 99.7m

B109 is located adjacent to the Green Track in the Serpentine area above B39. The entrance is a tight slot 1.8m long and 0.3m wide. After 1.2m the rift widens to 3m but constricts again 3.8m down to a hole in the floor 1m wide and 1.6m long. A climb of 3.2m leads to a second hole in the floor 0.45m in diameter. The climb continues for another 3m to where the cave bifurcates.

To the east a 3.9m climb leads a silt choked sump. The way on is to the west into the tight awkward squeeze with a strong breeze. After 3m the squeeze opens out into a chamber 1.2m wide and 3m high. The chamber floor slopes steeply at 55° for 5.8m down to a low crawl 1m long, which opens out into a rift 8.5m high and 0.6m wide. The rift is followed for 12m to a three way junction.

To the left the steep sloping flattener becomes silt choked and impassable after 5m.

To the right the passage, 0.5m high and 0.4m wide continues for 3m where the floor drops 0.8m below an oven 4.8m high. The passage constricts for 1.8m through the Duck Under Squeeze to another aven 1.8m high containing tree roots. Another squeeze 0.4m high and 0.7m wide is the way on. After 2m the passage opens out and drops 1.6m into a passage 1.2m high and 2m wide which continues for 12m and terminates.

Straight ahead is a rift 8m high and 1m wide. After 2m the rift drops away, directly above in the roof is the connection to B39. The floor slopes at 45° for 4m to a T-junction, To the right the passage slopes uphill and pinches out after 3m. To the left the floor slopes down for 10m and terminates.