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rence, at Fiesole, Artimino, Malmantile, &c. The direction
and dip of the strata do not appear to follow any constant rule.
They are subject to continual variation, and sometimes in the
same mountain--as, in Il Cimone di Fanano, they may be seen
dipping to different points.
: "The rocks hitherto mentioned constitute but a small portion
of the great chain of the Apennipes, and may be considered
only as the beginning of it. That which composes the princi-
pal part, and which, from its general distribution, may strict-
sy be termed the rock of the Apennines, is a limestone, but
quite different in its characters from that already spoken of. It
affords very little interest to the mineralogist ; and, as soon as
he enters its domain, he will traverse vast tracts of

country, without any other rock appearing from the foot to the summit of the mountain ; and he will pass whole days without meeting a single object to relieve the fatigue and tedium of his journey. Of this limestone are composed the high Apennines of Tuscany and of Romagna, those of Fabriano, Foligno, &c. It extends into the Abruzzi, through Puglia and Basilicata to the extreme point of Otranto: it is not certain whether it stretches into Calabria. Its prevailing colours are, pearl gray,dusky white, and pale flesh red; and sometimes it has a greenish tint. Its fracture is smooth, earthy, and without lustre; the fragments often assume a conchoidal form; and it is frequently traversed by stender veins and filaments of calcareous spar. It contains, in some places, beds of fetid limestone, as at Castellamare in the Bay of Naples, and in the neighbourhood of Salerno. Remains of marine animals are found in it, but not abundantly: casts of the Cornu Ammonis are the most common.

The limestone is identical with that of some of the Alpine mountains which surround the plain of Lombardy, along the territories of Como, Bergamo, Brescia, Verona, &c.: it also quite agrees with that of Dalmatia and Istria. The limestone of Jura, which some, without any apparent reason, have wished to distinguish as a particular formation, is in no respect different from that now described. Reuss has said, that the limestone of the Jura chain never contains flint or jasper; but Bernoulli informs us, that both these substances are found in the mountain of Jura itself. Flint, (or more probably chert), although not very abundant in the Apennines, is found in several places, -as in the mountain opposite the cascade of Tivoli, in those of Caserta, Benevento, &c. Reuss has called the limestone of Jura Höhlenkalk, or cave limestone, from the number of vast caverns existing in the mountains composed of this rock; but these are also of frequent occurrence in Italy, -as at Todi, Orvieto, Foligno, &c. This limestone is very barren, both in metallic and

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bituminous substances. Some slight indications of fossil coal have been found here and there in the lower parts of the Apennines; and at Castro and Trisulti, in the Campagna di Roma, mountain pitch has been collected from it in small quantity. The distinct stratification of this rock, its opacity and dullearthy aspect, and its occurring always above the rocks already mentioned, and never covered, except by the alluvial deposits, evidently fix its place among what are usually termed the secondary rocks. It is not confined to the principal chain of the Apennines, but extends also into the lower country, forming here and there detached hills. In the plain of Tuscany, (if that terin can be applied to so undulating a surface), it covers in many places the grauwacke and other older rocks; but in general only a small part of the limestone strata are seen, as they are covered either by volcanic matter, as in the Agro Romano and Campania, or by sand and marl, as in Tuscany, in the territory of Bologna, in Romagna, in the Abruzzi, &c. This is not the case, however, in Puglia Pietrosa ; for there, the bare limestone strata extend to the sea-shore, and are only occasionally concealed by a scanty coat of vegetable soil, or by a kind of shelly tufa; so that in planting the small trees which are cultivated there, such as the olive, the vine, and the carob-tree, they are obliged to break with mallets and iron bars the solid stony crust, in order to come at an intermediate layer of ochreous clay, where the roots may spread. In Tuscany, there are a great many hills of limestone, which are quite detached from the main body of the Apennines ; but it is remarkable, that in Romagna, throughout the whole of that long tract which extends from Bologna to Macerata, and even to Fermo, on the confines of Abruzzo, the only calcareous hill which is distinctly separated from the Apennines, is that in the neighbourhood of Ancona, forming a promontory on the sea-shore. In Puglia Pietrosa, however, there is a long continued chain of low hills

, (Le Murgie), which are separated from the Apennines by the plain of Capitanata, though they differ in no respect from them in the nature of the rock of which they are composed.

From what has been said, the primitive rocks cannot be supposed to exist very abundantly in the Apennines; and in fact they are only found at the two extremities of the great chain of these mountains, and are wholly wanting in the intermediate space. At both extremities there are found granite, clay-slate, mica-slate, and cristalline limestone. Granite is very abundant in Calabria, and it is also sometimes found in Liguria; as doni observed it in the neighbourhood of Sarzana, and Viviani in some other part of the Riviera di Levante. Mica-slate occurs in Eastern Ligurin, and at Massa di Carrara ; but it may VOL. XXVI. NO. 51.

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also be considered as extending further south towards the Mediterranean, as gneiss, which is only a modification of it, appears in the mountains of Montieri, Gerfalco, and Prata, in the Maremma Sanese. But these places are far distant from the calcareous Apennines; near which, in the opinion of M. Brocchi, not one of these rocks is to be found.

The primitive rock which chiefly predominates is serpentine. It forms, according to Viviani, the nucleus of all the Apennines in Eastern Liguria, where it is covered by transition limestone, as at Pignone, and in the neighbourhood of Spezia; and by clayslate, greenstone and grauwacke, at Chiavari, Lavagra, and Levanto. This rock is found at a considerable height in the Maritime, Grætian, and Pennine Alps; from whence it descends into Liguria with a continually decreasing level, until it no longer appears above the surface of the ground. Thus, while it constitutes the chief mass of many mountains in Liguria, which make a part of the principal chain of the Apennines, in Tuscany, on the contrary, it only composes hills of moderate elevatioii. The part of Tuscany where it occurs most abundantly, is near Impruneta, where it occupies almost the whole district between the Ema and the Greve; from whence it seems to extend a considerable way, as it is met with at Borgo San Stefano, in the neighbourhood of Anghiari, and in the territory of Gubbio. It forms the principal mass of the hills of Monte Nero, Valle Benedetta, and Sambuca, near Leghorn. In the territory of Volterra, it is seen between Montecatino and Miemo; also at Riparbella, near Bibona; and in the neighbourhood of Orbitello, which M. Brocchi considers to be the most southern point of its appearance along the coast of the Tyrrhene Sea.

Ît generally appears in detached masses, more or less extensive, which are separated from each other by intervals of several miles; but there is every reason to believe, that they are the more prominent parts of one general mass, which has been partially covered by other materials; these are in general grauwacke, galestro, (a kind of coarse-grained grauwacke-slate, containing a great deal of calcareous matter), secondary limestone, grey marl, and siliceo-calcareous sand. M. Brocchi considers it highly probable, that the serpentine is not only the primitive rock on which the secondary formations in the plain of Tuscany rest, but that it extends under the Apennines to the opposite side of the Peninsula; as he observed it in several places on the eastern side of these mountains. He saw it at Varana, about fifteen miles from Modena, and five from Sassuolo, where it rises in the form of an insulated rock, surrounded by calcareous sand, having solid beds of limestone interstratified. But the most considerable group he observed was at Vesale, where the hills of Pian del Monte, Serretta della Valle, Monte Giustino, and, aboạt four or five miles from these, Monte Specchio, are composed of a serpentine in all respects the same as that of Impruneta. , In the neighbourhood of Reno, it is accompanied by white primitive limestone, of a scaly fracture and semi-crystalline grain; and at Pian del Monte it is covered by black transition limestone. In that near Vesale, native copper is frequently found. The simple minerals that generally accompany the serpentine of Italy are, diallage of different varieties, asbestus, talc, calcareous spar, limpid quartz, and calcedony.; and at Miemo, that variety of bitter-spar described by Thompson, and named by him Miemite. But the mines ral which most generally accompanies it is the Jade tenace of Saussure; its colour is either white, greenish, or violet; it has in general little lustre, is of a scaly fracture, and slightly translucent on the edges. It is found in slender veins and nodules, incorporated with the serpentine, with which it has doubtless had a simultaneous origin;, and it is sometimes so regularly distributed in small pieces, that the mąss has a granitic structure, A mixture of this kind sometimes occurs, consisting of jade and serpentine, or of these two substances with diallage, or even of diallage and jade, without any serpentine; which last compounded rock has been called by the Florentines Granitone, Von Buch has given it the name of gabbro; but that term is applied in Tuscany to common serpentine. Granitone is found in almost every situation where serpentine exists; but the best opportunity of examining it, in all its relations, is at Figline, about three miles from Prato in Tuscany, where it is quarried for the purpose of being made into millstones. There is a section of it eighty or ninety feet high, where the internal structure of the hill may be seen: there are no signs of stratification in this rock, the continuity of the mass being only interrupted by irregular fissures. At Lornano, near Siena, there is a variety of granitone which deserves particular attention, from its resemblance to greenstone, and still more to sienite. It consists of a granular mixture of white jade and black diallage, which is so like hornblende, that they can hardly be distinguished in a polished specimen. Another granitone of the same kind, but having the component parts larger, is found at Bell Aria. If the close analogies that exist between jade and felspar, and diallage and hornblende, be considered, it will not be difficult to admit the conformity which granitone has with greenstone and sienite. And in fact, true greenstone and serpentine have been found contiguous, in the neighbourhood of Massa di Maremma, and at Riparbella in the territory of Volterra.

The wide and extensive valleys of Foligno and of Terni, and the country round Otricoli, are covered with vast deposits of limestone gravel, which continue as far as Borghetto and Civita Castellana, where they are partly covered by volcanic matter. The same thing occurs in Tuscany, in the Casentino, in Valdarno Superiore, in the neighbourhood of San Quirico, and of Raticofani. Siena is built upon a mass of calcareous breccia, containing pebbles of grauwacke. The hills round Benevento in the kingdom of Naples, those of Eboli between Salerno and Pesto, and many others in the Valle di Bovino in Basilicata, are composed of an aggregate of the same kind of pebbles, with the exception of those of grauwacke'; and vast tracts of the same kind of puddingstone occur in many parts of Romagna.

At the foot of the Apennines, there is a numerous series of bills which cover the greater part of the space comprehended between the high mountains and the sea, on both sides of Italy. They are distinguished, not so much by their lesser degree of elevation, which would be a vague and often a fallacious guide, as by the difference of their composition, and the epoch of their formation, which must have been posterior to that of the Apennines; in reference to which, they may be termed tertiary deposits. They are of very different degrees of elevation, and sometimes of very considerable height; the sandstone rock on which the capital of the little republic of San Marino is situated, belongs to this class; and Saussure has stated, (Voyages dans les Alpes), that the bottom of some vaults, which are near the summit of this rock, is from 320 to 330 toises above the sea.

These hills are composed of marl, and of sand and gravel lying over it; and a very slight examination is sufficient to show, that they have existed at the bottom of the sea at a period, geologically speaking, not very remote; for they are found to contain the trunks of trees almost in their 'natural state, the leaves of vegetables, the skeletons of fish, on which the dried flesh is still to be seen, and immense quantities of shells in which the gluten and colouring matter is often preserved; and frequently, the tendinous ligament which unites the two shells of the bivalves remains entire. While the strata of the calcareous mountains are always more or less inclined, sometimes vertical, and even tạrned over, the materials of these Sub-Apennine hills lie in general in a horizontal position,

The marl is of a bright grey, or dark leaden colour, inclining to blue, particularly when moistened. When it contains a considerable proportion of alumine, it becomes plastic with water, like common clay, and may be applied to the same purposes, It generally effervesces with acids, but is sometimes found with

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