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to 



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 -in. 



ired 







t a 

 .hat 

 was 

 ixty 



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 nth 



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 row 



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i 



ADDITIONAL NOTES. 



59^ 



advantage, and even injurious to land 



which has probably been 



owino- to their having ufed the magnefian lime, and having laid or 



too much of it, 



Mr. Tennant firfl found magnefian lime near the town of Don 



fter. and afterwards 



York, at Matlock in Derbyfliire, and 



Breeden in Leiceflerfliire, and at Workfop in Nottlnghamfli 



He 



obfer 



that the cathedral and walls 



f York are built with th 



magnefian limeftone 



and that at Matlock the magnefian and cal 



imeftones are contiguous to each other > the rocks on the fids 

 of the river Derwent, where the houfes are built, being magnefian 



and on the other fide 



He obferved alfo h 



th 



the 



magnefian limeftone was incumbent on the calcareous ; for in de- 

 fcendlng into a cave formed in that rock, he found a feparate vein of 

 calcareous limeftone, which was full of (hells, but contained no mag- 

 nefia -^ and obferves in general, that magnefian limeftone may be rea*- 

 dily diftingui(hed from the calcareous by its fo much flower folutlon 



inerally very few ftiells, but that 



in 



acids, and that it contains 



to 



thofe alfo are impregnated with magnefia. 



As all limeftone may be divided into three kinds ;, the rocks, whicli 

 remain, where they were formed from ftiells beneath the oc 

 cept that they were afterwards elevated by fubmarine fires ; 



dly into alluvial limeftone, as thofe which have been difiblved 



and fe 



water, and fimply precipitated 



the beds of chalk, which 



the moft 



foiuble remains of fea-animal 



as the teeth of 



fharks; and thirdly thofe which after having 



been dlfifolved 



d 



precipitated, have been long agitated beneath the fea, till the par- 

 tides have been rolled fo againft each other, as to acquire a globular 

 form, which is fald to rcfemble the roe, or fpawn, of fiffi, and v/hich 

 contain very few ftiells or none, as the Ketton ftone, and that which. 

 I have feen on Lincoln Heath extending almoft from Sleaford to 

 L 



Now as the falts of the fea confift of onfy 



kin<is, Gommoiv 



falt^ 



