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 tale, tremolite, 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 
the form of pyrite, but also from iron or manganese in the state of 
carbonate with the calcium, and alsofrom 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. da. Micaceous. e. Tremolitic; contains bladed 
crystallizations of the white variety of hornblende called tremolite. 
f. Graphitic; contairs graphite in iron-gray scales disseminated 
through it. g. Chloritic; 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, itis 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 limostone. The 
Carrara marbie varies in quality from coarse to frue statuary marble, 
and the best comes from Monte Crestola, and Monte Sagro. Out cf 
