384 DOMAIN V. CALCAREOUS. 



and palpably crystallised in all their parts ; they 

 are generally of a single colour, white, grey, 

 red, or black, and without any mixture of fo- 

 reign substances, except a small quantity ol 

 silex, which is intimately combined, and whose 

 presence is only found by dissolving them in an 

 acid. I have tried some of the purest specimens 

 in this manner ; I always obtained a quartzy 

 sediment; the quartz at times is so abundant^ 

 that these marbles yield sparks against steel. 



<c It is these large masses of homogenous mar- 

 bles which furnish the fine white statuary kinds, 

 such as those of Paros and Carrara : they are 

 never in any very elevated situation. 



" Those which are found interplaced between 

 schistose layers, or mixed with beds of serpen- 

 tine, yield the marbles called Cipolhie, which 

 present long veins parallel to each other, and 

 undulated in various directions. These may be 

 met with in the neighbourhood of the summits 

 of mountains. 



<c I have no need to mention that these mar- 

 bles never contain any vestige of shells, nor other 

 marine productions, as their formation is much 

 anterior to the existence of all organised bodies. 



" Some are found which contain garnets, oc- 

 taecfral iron, and even pyrites, the same as pri- 

 mitive schisti. Rome de ITsle says, that in, the 



