10 THE NATURAL HISTORY [LETT. 



the rain tears the slabs to pieces. 1 Though this stone is too 

 hard to be acted on by vinegar, yet both the white part and 

 even the blue rag ferment strongly in mineral acids. Though 

 the white stone will not bear wet, yet in every quarry at in- 

 tervals there are thin strata of blue rag, which resist rain and 

 frost, and are excellent for pitching of stables, paths, and courts, 

 and for building of dry walls against banks ; a valuable species 

 of fencing, much in use in this village; and for mending of 

 roads. This rag is rugged and stubborn, and will not hew to a 

 smooth face ; but is very durable : yet, as these strata are 

 shallow and lie deep, large quantities cannot be procured but at 

 considerable expense. Among the blue rags turn up some blocks 

 tinged with a stain of yellow or rust colour, which seem to be 

 nearly as lasting as the blue ; and every now and then balls of 

 a friable substance, like rust of iron, called rust balls. 



In Wolmer Forest, I see but one sort of stone, called by the 

 workmen sand or forest-stone. This is generally of the colour ot 

 rusty iron, and might probably be worked as iron ore ; is very 

 hard and heavy, and of a firm, compact texture, and composed 

 of a small roundish crystalline grit, cemented together by a 

 brown, terrene, ferruginous matter ; will not cut without difficulty, 

 nor easily strike fire with steel. Being often found in broad flat 

 pieces, it makes good pavement for paths about houses, never 

 becoming slippery in frost or rain ; is excellent for dry M'alls, and 

 is sometimes used in buildings. In many parts of that waste it 

 lies scattered on the surface of the ground, but is dug on Weaver's 

 Down, a vast hill on the eastern verge of that forest, where the pits 

 are shallow and the stratum thin. This stone is imperishable. 



From a notion of rendering their work the more elegant, and 

 giving it a finish, masons chip this stone into small fragments 

 about the size of the head of a large nail, and then stick the 

 pieces into the wet mortar along the joints of their freestone 

 walls : this embellishment carries an odd appearance, and has 

 occasioned strangers sometimes to ask us pleasantly " whether 

 we fastened our walls together with tenpenny nails." 



1 " Firestone is full of salts, and has no sulphur : it must be close grained, 

 and have no interstices. Nothing supports fire like salts ; saltstone perishes 

 when exposed to wet and frost." PLOT'S Staff, p. 152. 



