Silicifcrous Argillite. 3^ 1 Trap intimately mixed with Serpentine. I ommer is fahl to have found a ftone of this fort ; but I can find no defcriptionof it. Siüciferous Argillite. Lelke G. 153. This with the appearance of an argillite feems at the fame time intimately penetrated with fome »ftone of the fiticeous genus; generally fibceous lliiftus, orfand, orjafper, orbafanite, or quartz. Colour, dark, blackilh, or bluifli g re 7> g<*7 with black or deep blue blotches, or reddifh, or yellowilh grey, more rarely greemlh grey. FrÄurel'in th^rX^ b “ ° f n "S le >»- tn Somctimes the quartz feems the mofl conlidera- Me p”t oOhe compound, but flill preferves the flaty appearance; andthefeams are of a darker colour, as in the fpecimen, Lelke S. 747. Sometimes the filiciferous argillite is alfo ferru- ginous which renders it much heavier, as the fpe- firnen,’ Lelke O. 774- » hich “ 1 ”““fred its colour is dark Wurth grey, w.th vetns ofred, and fome of white quartz; its perfed mica; hardnefs, 9> 11 ,s but m p :f llaty. Trapiferous