Note 5 — Chapter VIII · GEOGRAPHICAL DISTRIBUTION OF COAL—GREAT COAL FIELD OF PENNSYLVANIA, VIRGINIA AND OHIO—COAL DEPOSITS OF ILLINOIS, INDIANA AND KENTUCKY—ECONOMIC HISTORY—CONDITIONS OF FORMATION.
Reading edition
The diamonds found in the Ural chain are supposed to be connected with the carbonaceous grits of the devonian and carboniferous periods, which have been transmuted into metamorphic micaceous rocks, and contain the diamonds between the flakes of mica, just as garnets occur in mica-schist. Captain Franklin discovered diamonds in Bundelkund, imbedded in sandstone, with coal beneath, and supposed to belong to the true carboniferous system.