Primitive Limestone- t2^ It frequently contains accidental ingredients, and thefe occur more frequently in the older than in the newer membersof the-feries. We lhall men- tionfome of thefe : i. $uartz. It.occurs in maffive pieces of greater or lei's magnitude, and fome- times alfd in cryftals. 2. Mica.* It fometimes oc curs in fuch quantity as to give the ftone a fiaty fra&ure. Thefe two foffils, namely, quartz and mica are the moft common accidental foffils that occur in primitive limeftone. The lefs frequent are the following ; common hornblende, aftynoli e albeit, ferpentine, talc, fteatite, tremolite, garnet, calc-fpar, and flate-fpar. 2. It occurs more or lefs diftin&ly ftratified. It was once the opinion, that granular aggregated itones, as primitive limeftone, granite, fiemte, greenftone, &c. were never ftratified. This, how ever is a miftake. Primitive limeftone alfo occurs in beds of greater or lefs magnitude : fometimes thefe beds are ihort and thick, and are then faid to form lying maflcs (liegende Stbcke) j fometimes the beds are fo thick as to form whole moun tains, but this latter is a rare occurrence. , There are feveral formations of primitive limeftone. The oldeft is that which occurs in gneifs ; the next in age is that in mica-flate ; and the neweft is that found in clay-flate. It increafes in quantity from the oldeft to the neweft period. 4. It frequently contains ores of different kinds, and thefe occur often in beds, but feldomer in eins The metalliferous beds contain ores of dif ferent