390 REPORT ON NATIONAL MUSEUM, 1886. 



quite variable, though some shade of red mottled with white usually 

 predominates. Some varieties are beautifully light pink and white, or 

 pink and deep-blue gray or greenish. The very common chocolate-red 

 and white variety is put upon the market as Lyonaise marble, and is 

 used largely for tiling, its natural color being often rendered darker by 

 oiling. 



Chemically the stone is a dolomite, though varying widely in com- 

 position in samples from different localities. Some samples show a very 

 decided brecciated structure, while in others this entirely disappears. 

 It is as a rule very hard to work, and, as exhibited in the capitol at 

 Albany, the surface is often disfigured by irregular cavities and flaws 

 which are rather unsightly. The color is said to fade on exposure to 

 the weather, and hence the stone is used mostly for interior work. 



An excellent outcrop of this marble occurs on the shore of Mallet's 

 Bay, in the town of Colchester. The strata at this point are nearly 

 horizontal, and in many places form the banks of the lake. One of the 

 best quarries is so situated that a vessel can be brought up alongside 

 and loaded with blocks with as much ease as they are usually loaded 

 upon carts or cars at inlaud quarries. The stone occurs in beds varying 

 in thicknes from 1 to 6 feet, and blocks of almost any size can be ob- 

 tained. It is hard to work, but as a consequence is very durable when 

 once finished, being not easily scratched or scarred. 



The best developments of the rock for marble quarrying are at Col- 

 chester, as already mentioned, Milton, Georgia, Saint Albans, and Swan- 

 ton. At the last-named place there also occurs a beautiful gray marble, 

 with angular fossil fragments of a white and pink color, identical with 

 the "Lepanto " marble of New York. There is also a fine and compact 

 dove-colored marble here, admirably adapted for decorative work, but 

 the quarries are now abandoned. 



The Plymouth marble, so called, is a quite pure dolomite, an analysis 

 by Dr. Hunt resulting as follows: 



Per cent. 



Carbonate of lime 53. 9 



Carbonate of magnesia 44. 7 



Osyde of iron and alumina 1. 3 



99.9 



The stone occurs in the talcose-schist formation near the center of 

 the town of Plymouth, at an elevation of 250 feet above the Plymouth 

 pond. Quarries were opened here about 1835, but were soon abandoned, 

 as the demand at that time was almost altogether for white marble. The 

 beds dip G0° to the east, and the quarry walls, which have been exposed 

 to the weather for twenty years, seem unaffected. In color the stone is 

 blue or bluish-brown, diversified with long stripes and figures of various 

 shapes in wdiite. It is fine grained and compact, splitting with equal 

 facility in every direction.* 



* Geology of Vermont, Vol. ii, p. 776. 



