150 THE MAKBLES OE ITALY. 



marked geological horizon throughout the whole of the metalliferous 

 chain of Tuscany, by its regular stratification and its characteristic 

 fossils, is generally of a more or less bright red colour, which is usually 

 very agreeable to the eye. It is quarried in several places. 



In spite of its compact character, however, it scales off very readily, 

 and is friable, vitreous, and full of cleavage planes ; in addition to 

 which it is usually only found in thin beds, which prevents it being 

 used for other than table tops and flooring slabs. It is very rarely 

 found of a fine uniform red colour ; when it is so it is usually less 

 defective, and sells at a higher price. The ordinary specimens are of 

 a light red colour, with ocellated marking (occMatd), and of a brecciated 

 structure. The specimens of this marble are exhibited in the Italian 

 collections from Spezia, Seravezza, Campiglia, and Camajore, at the 

 Exhibition. In the Central Appennines the middle lias is represented 

 by a red limestone, analogous to the preceding one, and which can be 

 used for similar purposes, as may be seen in the collection from Ascoli. 

 The upper lias also contains a red marble in some of the provinces. 



All the reel Italian marbles are obtained from one or other of these 

 liassic formations. 



Yellow Marbles. — By a peculiar alteration of its colour and 

 structure, the red ammonite marble is changed into a yellow granular 

 form, in the brocatellos and yellow breccias. The valley of Santa 

 Maria del Guidice, in the mountains of Pisa, the mountains of Carrara, 

 the Montagnola Senese, and many of the southern provinces, produce 

 marbles of this kind, which are more or less in demand. 



The most famous are the marbles of Sienna, represented by fine 

 specimens from the estate of Cerbaie, belonging to Count B. Tolomei, 

 and from the estate of Seniere, belonging to Mr. G. Nomis. The 

 marbles from the last-named property have not as yet been quarried 

 for sale, but the great beauty of its clear yellow colour, and the large 

 size of which the blocks can be obtained, together with the fine quality 

 of the statuary marble already worked at the same place, make these 

 quarries peculiarly interesting in an industrial point of view. 



The three remaining classes of coloured marbles are of an inferior 

 importance. The fine slabs exhibited by Count Orfini, of Fuligno, are 

 good examples of the reddish yellow limestones (ceciato) of close grained 

 and uniform texture, which occur in the alberese. The peculiar and 

 delicate colour of this rock renders it very suitable for ornamental 

 purposes. The quarry belonging to Count Orfini is capable of furnish- 

 ing a large supply, but up to the present time it has only been employed 

 in the immediate vicinity, where there is no great demand for it. 



A few specimens of inferior green marbles are to be seen in the 

 collection from Carrara. 



In the collection from Ascoli will be seen a breccia belonging to the 

 necomian system ; this is a red limestone, with white spots which are 

 produced by an intermixture of white calcareous pebbles. 



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