Invertebrate urban fossils, such as bivalves, gastropods and ammonoids are quite common in building stones. However, vertebrate fossils are very hard to find in building stones because they are much less common. Therefore, when Roger Mata Lleonart (@RogerMLL), a local geologist, saw this peculiar fossil on the pavement in a rainy afternoon, he was quite puzzled. Roger shared this photograph on Twitter and, with the help of the geographer and urban-fossil-enthusiast Xisco Xavier Roig (@xiscoroig), discovered that it was a cross section of a sea cow's skull.

This extraordinary fossil soon became quite popular and local newspapers wrote about it.

Oliver Hampe and Manga Voss, two experts on sea cows' Paleontology, visited Girona last June to investigate this fossil. The limestone slab was replaced with a slab of the same material and the fossil was analysed using a Computed Tomography Scan.