The collection of La Pedrera de Meià of the Natural History Museum in London was collected, between 1955 and 1960, by Dr. H.W. Ball, the former curator of palaeontology at the NHMUK, and by Frederick M. Wonnacott (Whalley and Jarzembowski, 1985).
There are about three hundred fossil fish specimens from a broad taxonomic spectrum, of which almost half refer to the leptolepiform genus Leptolepis. The collection of insects is also significant, among which are the holotypes of some taxa, such as the nymph of Mesopalingea leridae, the dictopter Artitocoblatta hispanica, the odonate Condalia woottoni, the hemipter Wonnacottella pulcherrima and the beetles Chrysobotris (?) Ballae and Eobelus solutus. Other specimens refer to Artitocoblatta colominase, some diptera larvae, a possible aleyrhodoid pupa, some indeterminate Geocorisae and specimens of uncertain taxonomic classification. Fossil plants also make up a significant part of the collection, with 413 specimens, including the holotype and paratype of the conifer Frenelopsis rubiesensis.