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Show 140 NEWER PLIOCENE PERIOD· [Ch. XI. an extinct rhinoceros and hippopotamus, in a cave in the neigh· bom·hood of Syracuse, where the country is composed entirely of the Val di Noto limestone. Some of the fragments in the breccia are perforated by lithodomi, and the whole mass is covered by a deposit of marine clay filled with recent shells*. 'rhese phenomena may, we think, be explained by supposing such oscillations of level as are known to occur on maritime coasts where earthquakes prevail, such, in fact, as have been witnessed on the shores of the Bay of Baire within the last three centuries t. For it is evident that the temporary submergence of a cave filled with osseous breccia might afford time for the perforation of the rock by boring testacea, and for the deposition upon it of mud, sand, and shells. The association in these and other localities of shells of living species with the remains of extinct mammalia is very distinct, and corroborates the inference adverted to in a former chapter, that the longevity of species in the mammalia is, upon the whol~, inferior to that of the testacea. This circumstance we are by no means inclined to refer to the intervention of man, and his power of extirpating the larger quadrupeds, for the succession of mammiferous species appears to have been in like manner comparatively rapid throughout the older tertiary periods. Their more limited duration depends, in all proba· bility, on physiological laws which render warm-blooded quadrupeds less capable, in general, of accommodating themselves · to a great variety of circumstances, and, consequently, of surviving the vicissitudes to which the earth's surface is exposed in a great lapse of ages :j:. Caves near Pale·rmo.-The caves near Palermo exhibit appearances very analogous to those above described, and much curious information has been lately published respecting them. According to Hoffmann, the grotto of Mardolce is distant about two miles from Palermo, and is 20 feet high and 10 • Hoffmann, Archiv. fiir Mineralogie, p. 393. B~rlin, 1831. Dr. Christie, Proceeuings of Geol. Soc., No. xxiii. p. 333. t Vol. i. chap. xxv. t See above, p. 48, and vol. i. chap. vi. Ch. XI.] BRECCIAS IN STClLIAN CAVES. 141 wide. It occurs in a secondary limestone, in the Monte Grifone, at the base of a rocky precipice about 180 feet above the .se~. From .the foot of this precipice an inclined plane, consistmg of horizontal tertiary strata, of the newer Pliocene period, extends to the sea, a distance of about a mile. a, Monte Grifone. b, Cave of San Ciro. No. 27. c, Plain of Palermo. d, Bay of Palermo"'· The .l imestone esc.a rpment was evidently once a s ea _c l '1f f., an d the ancwnt beach still remains formed of pebble s o f var·w us rocks, many of which must have been brought from places far remote. Broken piec~s of c~ral and shell, especially of oysters a~d pectens, are seen mtermmgled with the pebbles. Immediate}~ above the level of this beach serpulre are still found adh~rmg to ~he fac.e of the rock, and the limestone is perforated by hthodom1. WI thin the grotto also, at the same level, similar p~rforations occur, and so numerous are the holes, that the rock IS com~ared by Hoffmann to a target pierced by musket bha ll1s1 . · But m. ord. er to expose to view these marks o f b on.· ng-s e s m the mt~rwr o: the cave, it was necessary £rst to remove a mass of br~ccta, whiCh consisted of numerous fragments of rock and an Immense quantity of bones imbedded in a dark bro~n calcar~ous marl. Many of the bones were rolled as if partially subJected to the action of the waves Belo th' b · · . • W IS recCia, _whiCh Is about 20 feet thick, was found a bed of sand filled wlth sea-shells of recent species, and underneath the Ph*'! TJh is section l·S ~~· ven b y D r. Christie, as of the Cave of San Ciro.-Ed. New 1. ourn., No. xxm Its geogr h' 1 ·r precise] 'tl th . ap tca post wn and other characters agree so ther no.~:~ 1 that of Mardolce, uescribeu by M. Hoffmann, that it may be ano• or e same cave, or one immediately adjoining. |
