4008: Avellano, Torca del
Riolastras 30T 456199 4803002 (Datum: ETRS89. Accuracy code: U) Altitude 235m
Length 24m Depth 10m
Area position

This site has been explored and surveyed by the Grupo Espeleológico de Santander del C.A. Tajahierro. Their survey is published in Exploraciones en Solorzano (Santander) in Los Sótanos de la Tierra, No. 5, 1980, Santander (ref. 1980a). Unfortunately the entrance position (along with many others in the publication) is very unreliable although attempts have been made to alter the given Madrid grid reference through a Greenwich grid reference to an ETRS89 grid reference, seen above.
The site, named by the los lugareños, has not yet been located - but it is supposed to be in the vicinity of sites 4007, 4009 and 4010.

Reference: anon., 1980a; anon., 2014b (Easter logbook)
Entrance picture :
Underground pictures :
Video :
Detailed survey : from 1980a
Line Survey :
On area survey :
Survex file :