194 ' FLCETZ ROCKS.' Its colour ufually inclines more or lefs to green. Certain varieties are reddifh, and thefe are deno minated Sienitic Greenftone. When frefh, and rather large granular, it ufually exhibits a fimple ftrudture; when, on the contrary, it is difinte- grated, and fmaller granular, it occurs in globular and thefe again in curved lamellar diftina concre tions. Certain varieties approach to wacke, and thefe are ufually veficular, and form a kind of amygdaloid. 2. It is fometimes very difthaiy ftratified, and frequently occurs in veins. 3- It always occupies the upper part of this formation when the feries is complete. 2. Amygdaloid. Mandelftein.—Wernsr. i. This rock has ufually a balls of wacke, or of fine granular difintegrated and clayey greenftone, and the veficles are filled with calcfpar, litho- marge, green-earth, chalcedony, agate, quartz amethyft, and heavy-fpar. When thefe fubftances fall out, the rock acquires a veficular ftrudure, and in this ftiape it has been frequently defcribed as lava. Sometimes the veficles are empty. 2. It is a common repofitoryof the different kinds of agate. Agate, however, is not confined to the amygdaloid of this formation ; for it occurs in the greenftone of the independent coal formation, and alio in tranlition amygdaloid. 3-