Mineralogy. 33 
It is formed from a fediment which 
the water carries along with it. 
B. In continued ftrata, Marga indurata 
tls continuis. Hard flatty marie. 
SECT, XXIX. , 
F. Calcareous Earth united with a metallic 
calx, F erra calcarea metallis intime mixta. 
Here, as well as in the others, fuch a 
mixture or combination is to be underflood, 
as cannot be difeovered by the eye alone, 
without the help of fome other means. 
The fubjedts belonging to this divifion 
lofe the property of raifing an effervefcence 
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 
fliewn 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. 
I. Calcareous Earth united with Iron, ’Terra 
calcarea marte intime mixta. White Ipar-like 
Iron, Ore, Minera ferri alha, Th^ S^tahljlein 
or fV Hfes Eifenerz of the Germans. 
1. This ore, however, is not always white," 
but commonly gives a white pov/der when 
rubbed. 
2. It becomes black in the open air, as like- 
wife in a calcining heat, 
D 3, In 
