Desobstrucción y exploración de tres nuevas simas en la Sierra de Aralar (Larraitz - Ausa Gaztelu)

The discovery of three new cavities located in the Sierra de Aralar (Gipuzkoa, Basque Country) is described. His exploration was performed after unclog their mouths in two of the cases. In one of them they had to remove blocks. In the other was necessary to expand narrow steps by employing drill, chisels and maces. The cavities are part of the system Errekonta - Osinbeltz, developed in a band of Urgonian limestone (Early Cretaceous, Aptian age) under mount Ausa Gaztelu. Data on cave fauna are presented and probable genesis, evolution and hydrological functioning of the cavities is discussed.