MINERALOG Y. 33 



It is formed from a fedi merit which 

 the water carries along with it. 



B. In continued ftrata, Marga indurata ftra* 

 tis contimiis. Hard flatty marie. 



SECT, XXIX. 



F. Calcareous Earth united with a metallic 

 calx, Terra calcarea metallis intirae mixta. 



Here, as well as in the others, fuch a 

 mixture or combination is to be underflood, 

 as cannot be diicovered by the eye alone, 

 without the help of fome other means. . 



The fubjects belonging to this divifion 

 lofe the property of raifing an effervefcencc 

 with acids, when they are rich in metal, or 

 contain any vitriolic acid. However, there 

 have been found fome that contained twenty 

 or thirty per cent, of metal, and yet have 

 fhewn their calcareous nature by the nitrous 

 acid. 



There are no more than three metals hi- 

 therto known to be united in this manner 

 with the calcareous earth, viz. 



SECT. XXX. 



1. Calcareous Earth united with Iron, Terra 

 calcarea marte intime mixta. White Ipar-like 

 Iron Ore, Miner a f err i alba. The Stahljlein 

 or bVeifes Eifenerz of the Germans. 



1. This ore, however, is not always white, 

 but commonly gives a white powder when 

 rubbed. 



2. It becomes black in the open air, as like- 

 wife in a calcining heat. 



D 3. In 



