12 The Natural History 



prevailing within it, the rain tears the slabs to pieces.^ 

 Though this stone is too hard to be acted on by 

 vinegar ; yet both the white part, and even the blue rag, 

 ferments strongly in mineral acids. Though the white 

 stone will not bear wet, yet in every quarry at intervals 

 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 of 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 

 walls, 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 



^ '* Firestone is full of salts, and has no sulphur: must be close 

 {^rained, and have no interstices. Nothing supports fire like salts ; 

 saltstone perishes exposed to wet and frost." Plot's Staff.^ p. 152. 



