Geologically the Castelltallat range is made up of limestone and marl mountains oriented WSW-ENE.

Where there is no forest predominate meadow Aphyllantion or Brachypodium and shrubs specially Dorycnum pentaphyllum and rosemary.

It is remarkable for the presence of the gypsophilous plant named ruac (Ononis tridentata) in some small gypsum patches and the bastard balm (Melittis melissophyllum).

Since a few years it can see the griffon vulture (Gyps fulvus) fly, coming from the neighboring county of upper Solsonès.

The astronomical observatory was built close to the ruins of the ancient castle as part of the revitalization of the area after numerous forest fires.