438 
Geology. 
2L Mercury.-— This metal, in the form of cinnabar, 
occurs in beds and veins in primitive mountains, but in 
inconsiderable quantity ; it is in the ficetz or newer rocks 
that it appears in abundance. In primitive mountains 
the beds lie in chlorite- slate, and the veins traverse rocks 
of the same kind : In fiaetz- rocks the beds are accompa- 
nied with slate- clay and sandstone, and probably belong 
to the coal formation. The great mercury mines of Idria, 
that yield yearly upwards of sixty tons of mercury, are 
situated in this newer formation. 
We have still two metals to consider, viz. Iron and 
Platina. 
22. Iron. — It is the most universally distributed of all 
the metals. It forms a constituent part of the oldest gra- 
nite. The Kasanar in Siberia, and the magnetic rocks 
near Dannemora in Sweden, prove that iron exists in great 
quantities even in the older primitive rocks. Combined 
with sulphur, as iron-pyrites, it occurs, in great beds, in 
gneiss, mica-slate, and hornblende- slate. Other iron-ores 
occur abundantly in transition rocks. The floetz-rocks 
are also very abundant in iron : thus, the first or oldest 
fleetz -limestone contains great depositions of brown iron- 
stone, as is the case at Sommo Rostro in Biscay, Hutten- 
berg in Carinthia, and Tarnowitz in Upper Silesia. The 
same formation also includes a vast mass of sparry iron- 
stone in Stiria, which has been worked to an immense ex- 
tent, and with great profit, for 1200 years. The inde- 
pendent coal formation, which is supposed to be newer 
than fioetz- limestone, contains great accumulations of 
clay- ironstone. Clay- ironstone, and iron-sand, occur in 
the newest fioetz- trap formation ; and, lastly, great depo- 
sitions of bog iron-ore appear in the newest of all the 
classes of rocks, the Alluvial. 
23. Platina . — This metal occurs only in grains along 
'with gold and iron- sand, in the alluvial soil of the valleys 
