358 rocks. 



In the United States, a good material is obtained in Maine 

 at Barnard, Piscataquies, Kennebec, Bingham and elsewhere 

 also in Massachusetts, in Worcester county, in Boylston, 

 Lancaster, Harvard, Shirley, and Peperell ; in Vermont, at 

 Guilford, Brattleborough, Fairhaven, and Dummerston ; in 

 Hoosic, New York ; on Bush creek and near Unionville, 

 Maryland ; at the Cove of Wachitta, Arkansas. At Rutland 

 Vt., is a manufactory of slate pencils, from a greenish slate. 



These slate rocks are also used for gravestones ; and we 

 cannot go through New England cemetries without frequent 

 regret that a material which is sure to fall to pieces in a few 

 years, should have been selected for such records. 



Drawing slate is a finer and more compact variety, of 

 bluish and purplish shades of color. The best slates come 

 from Spain, Italy, and France. A good quality is quarried in 

 Maine and Vermont. 



Novaculite, hone-slate, or whet-stone, is a fine grained slate, 

 containing considerable quartz, though the grains of this 

 mineral are not perceptible. It occurs of light and dark 

 shades of color, and compact texture. It is found in North 

 Carolina, 7 miles west of Chapel Hill, and elsewhere ; in 

 Lincoln and Oglethorpe counties, Georgia ; on Bush creek, 

 and near Unionville, Maryland ; at the Cove of Wachitta, 

 Arkansas. 



Argillite is a general term given to argillaceous or clay 

 slate rocks. Many shales or argillites crumble easily, and 

 are unfit for any purpose in the arts, except to furnish a 

 clayey soil. 



Alum shale is any slaty rock which contains decomposing 

 pyrites, and thus will afford alum or sulphate of alumina on 

 Uxiviation. (See under Alum, page 128.) 



Bituminous shale is a dark colored slaty rock containing 

 some bitumen, and giving off a bituminous odor. 



Plumbaginous schist is a clay slate containing plumbago 

 or graphite, and leaving traces like black lead. 



The Pipestone of the North American Indians was in part 

 a red claystone or compacted clay from the Coteau de 

 Prairies. It has been named catlinite. A similar material, 

 now accumulating, occurs on the north shore of Lake Supe- 

 rior, at Nepigon bay. Another variety of pipestone is a dark 

 grayish compact argillite ; it is used by the Indians of the 

 northwest coast of America. 



Agalmatolite is a soft mineral, impressible by the nail. 



