[4] In 1989 a geology student at the Complutense University of Madrid, Francisco Hernández Arteaga, was waiting for his girlfriend next to the Faculty of Political Science at the Somosaguas campus when he discovered skeletal remains on the ground.

[2] Since then, excavations have been carried out regularly by students and since 2000 a fortnightly work period has been established in April or May, in addition to open days, workshops and exhibitions.

[8][note 1] The taxa identified belong to different groups: Gliridae (Microdyromys koenigswaldi, Microdyromys monspeliensis and Armantomys tricristatus), Sciuridae (Heteroxerus grivensis and Heteroxerus rubricati), Cricetidae (Megacricetodon collongensis, Democricetodon darocensis, Cricetodon soriae and Democricetodon lacombai), Insectivora (Miosorex grivensis and Galerix exilis), Lagomorpha (Lagopsis penai and Prolagus oeningensis) and Reptilia (Chelonia, Lacertidae and Anguidae).

[10] The fossils present in Somosaguas Norte correspond mostly to macrovertebrates, although microvertebrates have also been found, such as the lagomorphs Lagopsis and Prolagus oeningensis and the cricetid Democricetodoninae.

[8] As for macrovertebrates, remains of the mastodon Gomphotherium angustidens have been documented; fossils of the carnivores Hemicyon, Amphicyon, Pseudaelurus and an undetermined mustelid;[3] the equid Anchitherium; the rhinoceros Prosantorhinus douvillei; the ruminants Heteroprox, Tethytragus and Micromeryx and the suid Conohyus simorrensis.

[11] It seems that the main processes that have occurred in the deposit from the taphonomic point of view are:[11] Isotopic analysis of the fossil remains has shown that a cooling of the climate and an increase in aridity were taking place at that time.