KINDS OF ROCKS. 433 



the process all the fossils present were obliterated, except 

 in some cases of partial metamorphism. Its impurities are 

 often mica or talc, treniolite, white or gray pyroxene or scap- 

 olite ; sometimes serpentine, through combination with 

 which it passes into ophiolyte (p. 453) ; occasionally chon- 

 drodite, apatite, corundum. 



Varieties. — a. Statuary marble; pure white and fine grained. 

 b. Decorative and Architectural marble; coarse or fine, white, and 

 mottled of various colors, and, when good, free not only from iron in 

 tlie form of pyrite, but also from iron or manganese in the state of 

 carbonate with the calcium, and also from all accessory minerals, even 

 those not liable to alteration, and especially those of greater hardness 

 than the marble which would interfere with the polishing, c. Verd- 

 antique, or Ophiolyte. d. Micaceous, e. Tremolitic; contains bladed 

 crystallizations of the white variety of hornblende called tremolite. 

 f. Graphitic; contains graphite in iron-gray scales disseminated 

 through it. g. Ghloritic; contains disseminated scales of chlorite. 

 h. Chondroditic; contains disseminated chondrodite in large or small 

 yellow to brown grains. 



White and grayish-white marble is abundant in Western New Eng- 

 land, and Southeastern New York (Westchester County). The tex- 

 ture is less coarsely crystalline in Vermont than in Massachusetts, the 

 crystallization of the limestone as well as of the associated schists in- 

 creasing in coarseness from the north to the south, or rather south- 

 southwest, which is the trend of the limestone belt. Fine marbles 

 are quarried in Dorset, West Rutland, Pittsford, and other places in 

 Vermont, and the best of statuary marble occurs abundantly in Pitts- 

 ford. The whitest marble of Rutland is not as firm as that mottled 

 with gray, owing apparently to the fact that it was made white by the 

 heat that crystallized it burning out any carbonaceous material ; while 

 at Pittsford, 16 miles to the north of Rutland, it is very firm, and is white, 

 probably, because it was made with less heat from a whiter lime- 

 stone. In Vermont, the best quarries occur where the strata stand 

 at a high angle : the layers in such regions were subjected to great 

 pressure in the upturning that gave them this position, and this pres- 

 sure has soldered many layers together in one that are separate where 

 the pressure was less ; consequently blocks as large as an ordinary 

 house might be obtained at some of the quarries. Good marble is also 

 quarried in Pennsylvania, Maryland, and Tennessee. One of the most 

 beautiful marbles from deposits of crystalline limestone in the United 

 States, is the mottled reddish- brown from East Tennessee, and mainly 

 from Knox and Hawkins counties. Another handsome marble is the 

 mottled red of Burlington, Vt., from the semi-crystalline Winooski 

 limestone ; and a still finer the deeper red (or cherry-red), mottled and 

 veined with white, of Swanton, Vt., from the same limestone on the 

 northern borders of the State. 



The Carrara marble of Italy, the Parian, of the island of Paros (the 

 birthplace of Phidias and Praxiteles), and the Pentelican, from quar- 

 ries near Athens, Greece, are examples of crystalline limestone. The 

 Carrara marble varies in quality from coarse to true statuary marble, 

 and the best comes from Monte Crestola, and Monte Sagro. Out of 



