Peculiar interest of Spanish geology 58 Granite and Silurian rocks _ib._ Carboniferous formation 59 Secondary formations _ib._ Upper Cretaceous _ib._ Eocene tertiary 60 Miocene fresh-water _ib._ Pliocene _ib._ Influence of geology on populations _ib._ Statistics of Spanish geology 61 Volcanoes, recent _ib._ _Minerals of_: Gneiss and crystalline schists 62 Metamorphic rocks _ib._ Cambrian formation _ib._ Silurian slates _ib._ Devonian sandstones _ib._ Carboniferous series _ib._ Permian 63 Triassic conglomerates _ib._ Jurassic limestones and marl _ib._ Cretaceous formation _ib._ Eocene, Miocene, and Pliocene _ib._ Production and export of six chief minerals _ib._ Of argentiferous ore, cobalt, silver _ib._ Coal 65 Iron of the Bilbao district _ib._ Locality of principal mines 66 Mining laws 67 CHAPTER IV. ETHNOLOGY, LANGUAGE, AND POPULATION.