sentences:  In spite of that, caves with prehistoric settlements have been discovered in Piélagos, Rascaño and Salitre, one of the highest altitude (450 m over sea level) stations with paleolithic art.The medium valley of the Miera River, that mostly coincides with the municipality of Miera, is trapped between the abrupt karstic limestone pavements of "Porracolina" to the East, and "Las Enguizas" to the West, both belonging to the Urgonian Complex.In both limestone blocks, important karstification phenomenons take place; there have been relevant explorations in these complexes and solved labyrinths in the caves of "Alto del Tejuelo".