3^6 •' ‘ • dggregatel. Rubble Stone, Grauwacke of Werner. Gres Gris of the French. _ This is a particular kind of fandftone, contain- ing not only grains of quartz, filiceous fhiftus or hornftone, but alfo fcraps of bluilh argillite in ä clayey cement, and of this there is ofcen no more than is barely fufficient to hold the grains too-e- ther, fometimes with, and fometimes without mica; commonly compaft, fometimes llary in the grofs. ; 'j^f 0Ur ' s or bluifhgrcy, or dark reddtfh brown mixed wjth grev. Frafture, in the lniall, fine fplintery or earthy. Hardnefs, from 7 to 9, rarely so . Sp. gr. from 2,64 to 2,085, ^ut when withered, only 2 60 * See Lelke 0. 1278, and S. 474 , 607. Breccias. Tliefe are either fimple or compound ; fimple breccias confift of angular fragments of ftones of the famegenus, agglutinated or compatfted toge- ther; or of ftones of one fpecies imbedded in a cement of the fame genus, whether the fpecies be different or not. 1 hus a Calcareous Breccia confifis of fragments of marbles, of different colours, hefd together by a calcareous cement. This is often fimply called * Lalius mentions fome whofe fpec. prav. is ■j.j.:?. But the 3 feem3 an error of the prefs. Hartz. 143.