OF GEOLOGY: BEING AN INQUIRY HOW FAR THE FORMER CHANGES OF THE EARTH'S SURFACE ARE REFERABLE TO CAUSES NOW IN OPERATION. BY CHARLES LYELL, Esq. F.R.S. FOREIGN SECRETARY TO THE GEOLOGICAL SOCIETY OF LONDON. "The stony rocks are not primeval, but the daughters of Time.' IN FOUR VOLUMES. VOL. IV. THE THIRD EDITION. LONDON: JOHN MURRAY, ALBEMARLE STREET. 1835. PRINCIPLES OF GEOLOGY. BOOK IV. CHAPTER XII. OLDER PLIOCENE FORMATIONS. Geological monuments of the older Pliocene period — Subapennine formations Opinions of Brocchi- Different groups termed by him Subapennine are not all of the same age Mineral composition of the Subapennine formations Marls Yellow sand and gravel — Subapennine beds how formed Illustration derived from the Upper Val d'Arno mains of subapennine hills Organic re Older Pliocene strata at the base of the Maritime Alps - Genoa — Savona Albenga - Nice Conglomerate of Valley of Magnan — Its origin — Tertiary strata at the eastern extremity of the Pyrenees. Subapennine strata. We must now carry our retrospect one step farther, and treat of the monuments of the era immediately antecedent to that last considered. The Apennines, it is well known, are composed chiefly of secondary rocks, forming a chain which branches off from the Ligurian Alps and passes down the middle of the Italian peninsula. At the foot of these mountains, on the side both of the Adriatic |