62 OFSTONES. 



bury, Etall, and at Stony-path, near Aln-wick. Their furfaces are 

 all, more or lefs, fct with fplendid talcy particles, which pafs 

 the fire without lofing their luftre, at the fame time that the flate 

 crackles and burfts intofhivers, or lofes its natural colour. 



In the grounds at Overtoil, near Simonbnrn, on the eftate of Sir 

 Ralph Milbank, of Hannaby, in York/Jjire, Bart, is a flate of a bright 

 lead-colour, their furfaces extremely fmooth and mining with 

 filvery flakes of talc, the laminae diftinguifhed at the edges by 

 alternate deep blue, and ochreous yellow veins ; the flratum 

 fourteen inches and a half thick, faced with an irony, rufty-co- 

 loured ftone, which, on being ftruck with a hammer, falls off 

 like wooden laths. Above and under the flate is a large flag, each 

 from four to fix inches thick, dipping to the fouth, and rifmg to 

 the north; fome of the bottom-flags of an irregular and uneven 

 furface, as if bulged and bruifed with the weight of the incum- 

 bent roof. The roof is in fome places eighteen, and in others 

 twenty-four, feet. The flags are ufed for tomb-flones, and look 

 very handfome under cover, but are too tender to bear the 

 weather. They may be had of a very large fize. Both the flags 

 and flates are impatient of the fire and frofls. In the fire they 

 crackle, and burfl with a loud noife. like the report of a piflol, 

 owing to their fulphurs. Under the feverity of frofts and tem- 

 pefls, they feparate into thin leaves or plates, and moulder away. 

 If the flates had hardnefs equal to their lightnefs and beauty, 

 they would be the mofl valuable of any in the kingdom for 

 covering houfes. There are fome few, indeed, in the fame 

 quarry of another nature and colour, of a hardy ferrugenous 

 conflitution, and of a rufty hue, not altering by the torture of 

 fire, or by heavy rains, and piercing frofls. Thefe are ufed by 

 the country people in the neighbourhood in the ftrufture of their 

 flew-ovens. 



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