1869.] ROCKS CONTAINING ORGANIC SUBSTANCES. 453 



hjperite, between which the common crystalline rock.'^, gneiss, 

 hornblende, mica-schist and others, intervene. The bituminous 

 gneiss and mica-schist occur interstratified in common reddish 

 granite-gneiss at the western part of the high and precipitous 

 Nullaberg, occupying a thickness of more than twenty fathoms, 

 and extending along almost the whole side of the mountain. The 

 dip of the strata is about 70° eastward, and they are covered 

 first by a bed of hyperite and then with parallel strata of other 

 granitoid rocks. 



Generally, the bituminous substance is rather uniformly 

 distributed through the range, in the gneiss as well as in the 

 mica schist, and the entire mass has a black colour. The naked 

 eye is hardly able to discern any particles of coal. When coarsely 

 ground the rock resembles gunpowder, but when ground finer, it 

 grows darker, either of the colour of soot, or resembling pyrolusite. 

 When beaten with the hammer, it emits a bituminous smell, like 

 anthi'aconite, and also when heated by the blowpipe ; it then gives 

 a flame. When calcining 5. 32 grammes in an open crucible of 

 platinum, I was not able completely to burn the whole of the 

 bituminous substance, even after adding several times nitric acid ; 

 a little coal always remaining unconsumed. The loss of weight, 

 however, was 12.03 per cent; the ashes were gray. When 

 heated in a retort of thin iron plates, twelve pounds emitted 

 much combustible gas, while a yellow combustible oil, as well 

 as a colourless incombustible fluid wns collected in the recipient. 

 When the gas was allowed to escape through a hole of one inch 

 in diameter, a fine and bright flame was obtained during four 

 hours ; during the fifth and sixth hour the flame grew bluer 

 and fainter.- The powder in the retort remained as black as 

 before the distillation, though with rather a high lustre. It had 

 lost 15,6 per cent of its volume. — The specific gravity of the 

 rock is 2,19.* It is so loose, that a man may in about half an 

 hour sink in it a hole of two feet. 



On a closer examination of the bituminous strata it is very 

 diflScuit, from the general homogeneousness of the bed, to decide 

 whether and where it is gneiss or mica-schist, that is impreg- 

 nated with bitumen, but nevertheless one finds that both the 

 above-named rocks, and thin layers of chlorite schist constitute 



* "When weighed in the hand, it feels very light, compared with 

 silicates in general. 



