*28 PRIMITIVE ROCKS. ferent kinds, as lead-glance, blende, magnetic ironftone, magnetic pyrites, auriferous arfenic-py. rites, and native gold. The veins are very incon- fiderable, and by fome mineralogifts are faid to contain principally manganefe. 5* Several beautiful varieties occur in this coun try, as in the iflands Tiree, Icolmkill, and Skye; alfo m the county of Sutherland, and many other places. The marble of Sutherland is faid to be particularly valuable. The promontory of Athos, in the Archipelago, is faid to be compofed of pri mitive limeftone; alfo the Ifland of Paros, and part of the Appenines, as about Carrara and Maf- fa, many parts of the Alps of Switzerland, the Pyrenees, Carrapatos in Portugal, Uld in Suder- manland, Bohemia, Saxony, Silefia, and many other parts of the continent of Europe. 6. Primitive Trap. Ur-Trap. —Werner. Trapps Primitifs, Brochant. The rocks belonging to the trap formation are placed immediately after thofe of the clay-flate formation, becaufe they both occur firft in confi derable quantity in clay-flate, and feem more inti mately connedted in various relations with that rock, than with mica-flate or gneifs. i. The name trap is derived from the Swediflx word trappa, lignifying a flair. The Swedes applied