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Show CHAPTER XV. Miocene period-Marine formations-Faluns of Touraine-Comparison of the Faluns of the Loire and the English Crag-Basin of the Gironde and Landes -Fresh-water limestone of Saucats-Position of the limestone of BlayeEoceno strata in the Bordeaux basin-Inland cliff near Dax-Strata of Piedmont- Superga-Valley of the Bormida-Molasse' of Switzerlaad-Basin of Vienna-Styria-Hungary-Volhynia and Podolia-Montpellier. MIOCENE FORMATIONS-MARINE. HAviNG treated in the preceding chapters of the older and newer Pliocene formations, we shall next consider those mem~ hers of the tertiary series which we have termed Miocene. The distinguishing characters of this group, as derived from its imbedded fossil testacea, have beeh explained in the fifth chapter (p. 51). In regard to the relative position of the strata, they underlie the older Pliocene, and overlie the Eocene formations, when any of these happen to be present. The area covered by the marine, fresh-water, and volcanic rocks of the Miocene period, in different parts of Europe, can ah·ead y be proved to be very considetable, for they occur in Touraine, in the basin of the Loire, and still more extensively in the south of France, between the Pyrenees and the Gironde. They have also been observed in Piedmont, near Turin, and .in the neighbouring valley of the Bormida, where the Apennines branch off from the Alps. They are largely developed in the neighbourhood of Vienna and in Styria; they abound in parts of Hungary; and they overspread extensive tracts in Volhynia and Podolia. Shells characteristic of the Miocene strata are found in al1 these countries, figures of some of which are given in Plate 2 in this volume. They characterize the period, because they are either wanting or extremely rare in the Eocene or Pliocene formations. We shall now proceed to notice briefly some of the countries Ch. XV.] FALUNS OF TOURAINE. 203 before enumerated as containing monuments of the era under consideration. Touraine.-We have already alluded to the proofs of superposition adduced by M. Desnoyers, to show that the shelly strata provincially called 'the Faluns of the Loire' were posterior to the most recent fresh-water formation of the basin of the Seine. Their position, therefore, shows that they are of newer origin than the Eocene strata,-more recent, at least, than the uppermost beds of the Paris basin. But an examination of their fossil contents proves also that they are referrible to that type which distinguishes the Miocene period. When three hundred of the Touraine shells were compared with more than eleven hundred of the Parisian species, there were scarcely more than twenty which could be identified; and, on the other hand, the fossil shells of the Touraine beds agree far less with the testacea now inhabiting our seas than does the group occurring in the older Pliocene strata of northern Italy. The Miocene strata of the Loire have been observed to repose on a great variety of older rocks between Sologne and the sea, in which line they are seen to rest successively upon gneiss, clay-slate, coal-measures, Jura limestone, greenstone, chalk, and lastly upon the upper fresh-water deposits of the basin of the Seine. 'l'hey consist principally of quartzose gravel, sand, and broken shells. The beds are generally incoherent, but sometimes agglutinated. together by a calcareous or eatthy cement, so as to serve as a building-stone. Like the shelly por~ion of the crag of Norfolk ahd Suffolk, the faluns and assoCiated strata are of slight thickness, not exceeding seventy feet. They often bear a close resemblance to the c~ag in appearance, the shells being stained of the same ferru? mous co!our,. and being in the same state of decay ; serving In Tourame, JUSt as in Norfolk and Suffolk, to fertilize the arabi~ land.. Like the crag, also, they contain mammiferous remai~s, WhiCh are not only intermixed with marine shells, but sometimes encrusted with serpuloo, flustra, and balani. These |