Independent Coal Formation. 179 ■trap contaias diftmft pitcb-coal, columnar coal, and conchoidal glance-coal. The alluvial formation contains almoft exclufively earth-coal and bitumi nous wood. Werner mentions the following as formations that do not belong to any of the preceding : 1. The fmall and low beds of coal that occur in fandftone at Wenigkrawitz in Silefia. It is con- je&ured to occur in the third fandftone formation. 2. The fingle beds of coal that occur in flcetz- limeftone, and which are in general of no very great importance. Thefe have been obferved in different places, as on the fhore of the Lake of Zurich, alfo in Franconia, and Thuringia. 3. The bituminous marl-llate, from its contain ing fometimes portions of coal, may be conlidered as a fubordinate formation. We {hall now defcribe the independent coal formation, and {hall confider the others when we come to treat of the floetz-trap and alluvial rocks. Independent Coal Formation, or Proper Coal For mation. Eigentliche Steinkohlen Formation.—Werner. 1. This formation, befides coal, contains three rocks which ?re nearly peculiar to it: thefe are, a conglomerate, and more lately about two miles from Weft Craigs, on the great road from Edinburgh to Glafgow. At this latter place there is a bed of flaty glance-coal from ten inches to two feet * thick, contained between beds of flate-clay, and covered by fan'dilono.
