Monumento Natural de La Fuentona, Calatañazor

La Fuentona is a natural spring that gives rise to the source of the river Abión, in the province of Soria. The whole of the spring and its natural environment was declared a natural monument on 12 November 1998 by decree 238/1998. It is located in the municipalities of Cabrejas del Pinar and Muriel de la Fuente.

The special characteristics of this natural space that give it a differential value and have made it the object of protection are: Example of aquifer and upwelling accompanied by small springs within a hydrological system. It preserves faunal communities of singular rarity, which constitute invaluable samples of genetic material in extreme danger of disappearing. Maintain its own geological and geomorphological formations, such as karst systems and complexes, forming part of the most extensive of those existing in its territorial area.