Trap, 227 f *4th Species. Trap. Of this I diftinguifh two families, the common, or amorphous, and the figurate. 1 ft Family. Common Trap. Bafalt of Werner. Its moft ufual colours are the greyifh or bluifh, or purplilh black; more rarely blackiih, or red- dilh brovvn (as in the bafis of mandelftein or toadftone) or greenifh grey; traps of the laft colours feem to me to be mixed vvith other fpecies. Found in large mafles, and frequently contain- ingbafaltine, quartz, calcareous fpar, calcedony, zeolite, hyalite, felfpar, (trap porphyry,) and olivin. Hence it is frequently found porous, cellular, and cavernous, from the decompofition and falling out of thefe ftones. Externally it has frequently a brown or reddifti brown rind, from decompofition. Luftre, o; or from Ihining particles of bafal- tine difperfed through it; fee LefkeS. 102, 835. Tranfparency, o. % tradture, earthy, or fine fplintery, often un- cven. Fragments 2,3, often tending to a qua- drangular form. 0.2 Ic