MODE VIII. ORSTEST* 4S 1 



covered by Ramond to form the summit of Mont 

 Perdu, the highest of the Pyrenees. It is gene- 

 rally of a black colour; but some specimens 

 from Derbyshire are even white, or at least 

 whitish grey. The other tints are chiefly va- 

 rious greys, with brown and Isabella yellow. 



Mr. Kirwan says that the smell is urinous or 

 alliacious; and that it abounds in the county of 

 Gal way, in Ireland, where, as fuel is scarce, it is 

 often employed to heat the rooms, and remains 

 hot for many hours. In the neighbourhood of 

 Vesuvius it is found laminar, alternately white 

 and yellow. It often produces excellent lime. 



A grey Flemish marble, now much used at 

 Paris, belongs to this kind, and leaves a very 

 fetid smell in the manufactories. That of the 

 summit of Mont Perdu is a black marble, im- 

 pregnated with shells and sand. Ammonites 

 and camerines, gryphites, pectenites, with mad- 

 repores, and other zoophytic remains, enter into 

 the composition of the singular calcareous chain 

 of the Pyrenees. 



Black orsten, from the summit of Mont Perdu. 



Grey, with zoophytic remains, from Flanders. 



In yellow and white plates, from Vesuvius. 



Greyish white, from Derbyshire. 



VOL. I. 



