1‘Barrocal’ could be understood like clay (barro, in Portuguese and Spanish) plus lime (cal, idem), meaning –in real physical terms– a fine layer of clay –mostly 10 to 20 cm of clay– over an extensive mass of lime rock. It is a zone where water infiltration is very important and leads to a progressive dissolution of limestone; a karstic process takes place, forming big aquifers with various depths, normally reaching hundreds of meters (Costa et al. 1985). Nevertheless, according to a famous dictionary of Portuguese language (Machado 1991), the term barrocal comes from barroco meaning an isolated big rock or a place full of big rocks.