We are presenting the finding of a new site of vertebrate fossils in Cº Batallones (Torrejón de Velasco), which is situated in the southern area of the Madrid basin. The site lies in facies which correspond to the top of the Miocene Intermediate Unit than now can be dated as Upper Vallesian, estimated age of the accompanying faunal assemblage. The accumulation of fossil bones is notable for the grand diversity and overwhelming predominance of carnivors (more than 98% of the remains), which suggests the existence of a natural trap responsible for the unusual ossiferous accumulation.Peer reviewed