feet
below the surface of the soil, in a conglomerate of rounded stones
under two distinct layers; the uppermost, a mixture of sand, gravel,
and loam; and the other, thick black clay or mud."
DIAMOND MINES OF BRAZIL.
Brazilian
diamonds are found in the district of Minas Geraes, at San Paulo, in
the beds of various rivers, and at Serro Frio, or Cold Mountain, a
lofty plateau measuring eight leagues by sixteen. The most productive
districts of late are Matto Grosso and Bahia.
The
diamonds occur usually in alluvial soil, enveloped in a conglomerate
formed of rounded white quartz pebbles and light-coloured sand. The
miners have names for each variety of soil ; as—
Grupiara, the unused bed of a river.
