BUILDING AND ORNAMENTAL STONES. 471 



southerly course as far as Barnard. The slate found in this differs from 

 that of the eastern belt in that it splits more readily into thin sheets, 

 is not so distinctly laminated, and is more uniform in color, " being 

 nearly black and apparently free from the traces of iron oxides." A 

 single quarry is now in operation in this belt, that of the Adams Slate 

 Company, in Northfield, Washington County. 



The western and most important of the slate belts of this State ex- 

 tends from a point near the town of Cornwall, on the north, southward 

 through Castleton, Fairhaven, Poultney, Wells, and Pawlet, and passes 

 into the State of New York at Granville. In this slate it is stated 

 " there is a marked difference between the stratification and cleavage 

 planes, the dip of the latter being greater than the former." In color 

 the slates of this region are said to closely resemble those of Wales, 

 being of a dark purple, with blotches of green, Avhile some of the strata 

 are green throughout. In some portions of the formation a red slate 

 occurs, similar to that found across the line in New York State= This 

 variety is not, however, now quarried. This western area furnishes the 

 most fissile and valuable slates of the State, and, as will be seen by 

 reference to the tables, is very extensively worked. The slate is soft 

 and uniform in texture, and can be readily planed or sawn with a steel 

 circular saw, such as is used in sawing lumber. It is well adapted and 

 extensively used, not only for roofing purposes, but for school slates, 

 slate-pencils, blackboards, table-tops, mantels, etc. It is very exten- 

 sively marbleized. It is stated by Professor Hitchcock* that the first 

 quarry opened in this region was that of Hon. Alanson Allan, who be- 

 gan the manufacture of school slates at Fnirhaven in 1845. 



Virginia. — On Hunt Creek, a tributary of Slate River, in Buckingham 

 County, in this State, there occur extensive deposits of blue-black slate 

 of a quality suitable for a variety of uses, although they are now used 

 almost altogether for roofing purposes. The principal quarries now 

 worked are at or near the towns of Buckingham, New Canton, and Ore 

 Banks. Another belt of slate of the same geological age (Archaean) as 

 that just mentioned is stated to occur near the southeast base of the 

 Blue Ridge, in Amherst and Bates Counties. Very few samples of any 

 of these have as yet come into the Museum collection. 



Although frequently found in the collections of amateur mineralo- 

 gists, this substance can not be considered a true mineral, but is rather 

 an indurated clay.f It therefore varies greatly in composition, as it 

 does also in color and degree of induration. The usual color is a deep 

 though dull red, often beautifully flecked with small yellowish dots. 

 This form is soft enough to be readily cut with a knife, but is sufficiently 

 firm and compact to retain the sharpest edges and lines that may be 



* Op. cit., p. 796. 



tSee Analyses, Geol. Minnesota, Vol. i,p. 542. 



