1911 Encyclopædia Britannica, Volume 15… (1911)
“ It is the centre of a district very rich in minerals, obtained from a narrow stretch of crystalline schists underlying the Tertiary deposits. Iron ores (60 to 70% of iron) , copper ores, colours, brown coal, graphite, slate, and lithographic stone are obtained—nearly 2,000,000 tons of iron ore annually. ”
