3721: Lenny's Cave
Secadura 30T 455283 4799449 (Datum: ETRS89. Accuracy code: G) Altitude 61m
Length 477m Depth 9m Vertical range 16m
Area position

Updated 30th November 2012; 29th January, 6th March, 1st May, 9th October 2013; 26th September 2014; 5th October 2015

The western entrance (Lenny's 1) (GPS'd and surface surveyed, above) was found as an open and draughting hole sloping into a chamber. The route led into a narrow draughting rift after excavating a sand blockage. The rift was enlarged and allowed exploration to proceed.

After a short crawl, a chamber is reached with a hole down on the left leading into an enlarging passage to a junction with a major tunnel going off in both directions.

To the east, the passage (up to 10m wide) slopes down to a tiny stream that presumably feeds La Bodega, passes a route heading north ending at a boulder choke with tree roots and spiders then closes down at a boulder choke with further possibilities in the roof - possibilities exist here both to the east and the south. On the eastern side and after leaving the main passage, Lugger's Lair has been dug through to a 5m diameter, stooping height chamber with no way out. A crawl through into passage on the left leads to the second, easier entrance (Lenny's 2). Just where the main passage is left behind, a bone embedded in calcite is encountered in a small passage to the west.

To the west, the tunnel passes a phreatic rift on the left (with a possible climb) then closes in just after skirting a pit in the floor. Straight on, to the north, is a climb up to a gap between a rock wall on the left and boulders on the right which might deserve a bit of snappering. The way on is down a 3m drop (currently tackled with a tatty ladder) to a slope up to a choke. A hole through at the top leads into the choke and a dodgy dig. On the left, before the choke, is The Grunt, an excavated crawl into another bouldery area where a strong, cold draught coming down through a hole in the boulder choke is the obvious though difficult dig.

The chokes at both ends of the cave were looked at again in August 2013 and a choke just before the p4 at the western end of the cave was capped, but may require snappers. There is little or no draught at that point. The western choke was snappered in 2015 but the 2m extension shows passage that is too narrow with no draught.

In August 2015, a rift was climbed into on the N wall which narrowed down.

Biological sampling was untaken as part of a research project at Easter 2014. Over Easter 2018, the Matienzo Karst Entomology Project (led by Tom Thompson) followed up a previous study by collecting bugs, spot sampling and setting pitfall traps in a number of sites under a Cantabria-wide permit. The Entomology Project carried out some work in this cave.

The current survey shows the unsurveyed sections in green and indicates the leads to look at. In total, the cave will be over 500m long. There appeared to be an issue with either the GPS readings for the entrances, and / or the GPS for La Bodega and / or the survey but this was cleared up with a surface survey and more GPS reading at Christmas 2012.

Reference: anon., 2012d (summer logbook); anon., 2012f (Christmas logbook); Corrin Juan, 2013a; anon., 2013b (Easter logbook); anon., 2013d (summer logbook); anon., 2014c (summer logbook); anon., 2015c (summer logbook)
Entrance pictures : summer 2012 : Easter 2013
Underground pictures : December 2012 : summer 2012 : Easter 2013 : summer 2014 : summer 2015 : Easter 2018
Video : Christmas Day 2012 (YouTube)
draughting entrance, autumn 2012 (YouTube) : summer 2012 (YouTube)
Detailed Survey : pdf after summer 2012 : pdf after December 2012 and slight amendment October 2013 : pdf with amendment, 2015
Line Survey :
On area survey :
Survex file : yes (Amended magnetic declination December 2013 to align with Eur79 grid and coordinates altered to fit ETRS89 datum, April 2014.)
on area survey (Amended magnetic declination December 2013 to align with Eur79 grid and coordinates altered to fit ETRS89 datum, April 2014.)
Passage direction rose diagram: 1/7/2018