470 REPORT ON NATIONAL MUSEMM, 1886. 



ders,* and which it seems unnecessary to repeat here. The slates pro- 

 duced are all of a blue or blue-black color, and are used for all purposes 

 to which such material is usually applied. In the manufacture of school- 

 slates a softer and finer grade of material is requisite than for most 

 other purposes. These are split from the block in the same manner as 

 roofing-slates, their edges trimmed with a circular saw, and the faces 

 smoothed by a drawing- kuife, after which they are rubbed down with a 

 cloth and fine slate dust till the surface is smooth and even. They are 

 then mounted in wooden frames and packed for shipment. 



The following statistics of shipments from the Slatington region for 

 the year 1882 will give some idea of the magnitude of the industry : f 



Squares of roofing slates, 100,000 ; cases of school slates, 29,704 ; cases 

 of blackboards, 1,171; cases of mantels, 71; mantels (pieces) 2,704; 

 cases of hearths, 6 ; cases of flagging, 173 J ; flagging (pieces) 16,643 ; 

 cases of sawed slate, 15; cases of pencil slate, 3; making a total by 

 weight of about 29,920 tons for the year. 



South Carolina. — Clay slates are stated f to occur in this State in a 

 broad band extending along the edge of the Tertiary formations from 

 Edgefield County, on the southwest, to Chesterfield, on the northeast. 

 The present writer has seen none of this material nor has he any knowl- 

 edge regarding its adaptability for any form of architectural work. 



Texas. — Bluish-black slates of a jointed and thinly stratified struct- 

 ure, resembling the surface slates of New Hampshire and Vermont, 

 and promising of great utility, are stated to occur in Llano and Presidio 

 Counties. § The writer has seen none of these. 



Vermont — The roofing slates of Vermont are stated by Professor 

 Hitchcock || to exist in three distinct and nearly parallel belts, occupy- 

 ing the eastern, middle, and western portions of the State. The east- 

 ern belt extends from Guilford, one of the most southern towns in the 

 State, to Waterford, and probably as far north as Burke, in Caledonia 

 County, where it is cut off by an immense outcrop of granite. The slate 

 of this belt differs from that of the other divisions in presenting a more 

 laminated appearance, resembling closely a mica schist, the cleavage 

 corresponding closely with the lamination, which varies, if at all, but a 

 trifle from the planes of stratification. The stone is represented as of 

 good color, tough, and durable. Besides for roofing purposes it was 

 used largely for tombstones prior to 1830, when marble began to be 

 used in its place. The first quarry opened in this belt is stated by the 

 above authority to have been that of the New England Slate Company^ 

 who commenced operations in 1812. At the present time, so far as the 

 author is aware, no quarries whatever are worked in this belt. 



The middle range of slate extends from Lake Memphremagog in a 



* Rep. D 3, Second Geol. Surv. of Pennsylvania, Vol. I, 1883. pp. 83-160. 

 tFrom Rep. D% 2d Geol. Surv. Pennsylvania, p. 144-146. 

 | South Carolina, Resources, Population, etc., 1883, p. 133. 

 ^Second Ann. Rep. Geol. of Texas, 1876, p. 26. 

 || Geol. of Vermont, Vol. n, 1861, p. 791. 



