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Show 66 NEWER PLIOCENE PERIOD· [Ch. Vl. d d in unequal quan-sedimentary matter of different kin s, an tities at particular seasons of the year. '1 t 1 . ' · d preval s no on y m The great limestone, above mentwne ' f th . 1 d · the centre o e IS an the Val di Noto, but reappears m ' ·n the hill of Castrogiovanni, at the height of three thou-cappl g h 1 1 f t1 e sea. It is cavernous there} as sand feet above t e eve 0 1 • d . d S . and contains fossil shells an casts of at Sortmo an yt acuse, . * shells of the same species . (b d. N 5) Schistose and a?·enaceous limestone, ~c. ' Jagra~ o. ·~ . b ntioned passes downwards mto a white The hmestone a ove-me .. d l · h has sometimes a tendency to an oohtlc calcareous san , w uc . . and pi·s o1 1' t1· c struc t ure , analoaous to that which we have described o . . .. h l · f the travertin of T1voh -f. At Flondta, near w en spea nng o S 't contains a sufficient number of small calcareous yracuse, 1 • pebbles to constitute a conglomerat:, where also beds of sandy limestone are associated, replete w1th numerous frag.ments of shells, and much resembling, in structure, the En~hsh cornbrash. A diagonal lamination is often observable I.n the cal-ndy beds analoaous to that represented m the first careous sa b volume (chap. xiv. diagram No. 6), and to that exhibited in many sections of the English crag, to which we shall after-wards allude. In some parts of the island this sandy calcareous division~ b, seems to be represented by yellow sand, exactly resembling that so frequently superimposed on the blue shelly marl of the Subapennines in the Italian peninsula. Thus, near Grammichele, on the road to Caltagirone, beds of incoherent yellow sand, several hundred feet in thickness, with occasional layers of shells, repose upon the blue shelly marl of Caltagirone. When we consider the arenaceous character of this formation, the disposition of the laminre, and the broken shells .sometimes imbedded in it, it is difficult not to suspect that It was "' Dr. Daubeny correctly identified the Val di Noto limestone of Syracuse with that of the summit of Castrogiovanni.-Jamcson, Ed. Phil. Journ., No.xxv.p.J07, July, 1825. t Vol. i. chap. xii. Ch. VI.] SICILY-VAL Dl NOTO, 67 fanned in shallower water, and nearer the action of superficial currents, than the superincumbent limestone, which was evidently accumulated in a sea of considerable depth. If we adopt this view, we must suppose a considerable subsidence of the bed of the sea, subsequent to the deposition of the arenaceous beds in the Val di Noto. Blue marl with shells (c, diagram No. 5).-Under the sandy beds, last mentioned, is found an argillaceous deposit of variable thickness, called Creta in Sicily. It resembles the blue marl of the Subapennine hills, and, like it, encloses fossil shells and corals in a beautiful state of preservation. Of these I collected a great abundance from the clay, on the south side of the harbour of Syracuse, and twenty species in the environs of Caltanisetta, all of which, with three exceptions, M. Deshayes was able to identify with recent species*· From similar blue marl, alternating with yellow sand, at Caltagirone, at an elevation of about five hundred feet above the level of the sea, I obtained forty species of shells, of which all but six were recognized as identical with recent species t. The position of this argillaceous formation is well seen at Castrogiovanni and Girgenti, as represented in the sections, diagram No. 5. In both of these localities, the limestone of the Val di Noto re-appears, passing downwards into a calcareous sandstone, below which is a shelly blue clay. Strata beneath the blue marl.-The clay rests, in both localities, on an older series of white and blue marls, probably belonging to the tertiary period, but of which I was unable to determine the age, having procured from it no organic remains save the skeletons of fish which I found in the white thinlylaminated marlst. "' See list of these shells, Appendix II. t See Appenuix II. t I found these fossil fish in great abundance on the road, half a mile northwest of Radusa, on the road to Castrogiovanni, where the marls are fetiil, and near Castrogiovanni in gypseous marls, nt the mile-stone No. 88, and between that and No. 89. Lord Northampton has since rresented to the Geological Society 1•' 2 |