A new ichnofossil-Lagerstätte from the Miocene Vilanova Basin (NE Spain) is described. It is characterized by bioerosion structures that are exceptionally preserved as positive casts, many associated with internal and external molds of mollusk shells (gastropods and bivalves). Five main ichnotaxa were identified: Caulostrepsis contorta, C. taeniola, Entobia cateniformis, E. geometrica, and Gastrochaenolites dijugus, produced by annelids, sponges and bivalves, respectively. Combination of ichnological, taphonomical, and systematic data allows the concentration to be interpreted as the result of several storm events that mixed shells from a diverse array of marine environments during the biostratinomical phase. Bioerosive episodes took place before and after storms, and diagenetic processes produced external and internal shell molds and fine casts of the borings.