in South Australia. 171 



their appearance in snch a form, and I should have been spared 

 any investigation. The stone, however, of which they are 

 composed is not of volcanic origin, but is a quartzos'e granular 

 stone, probably eurite, and though crystalline, bearing distinctly 

 lines of former stratification. Taking this fact into considera- 

 tion, a great many difficulties arise in the way of an explanation 

 of the origin of these bands. There is something so different 

 in these appearances from any geological observations made 

 elsewhere, something altogether so original, that the experience 

 of others becomes useless as a method for finding a clue, and 

 one must set to work entirely unaided. Fortunately the rocks 

 in the immediate neighbourhood help us a little. On either 

 side of the chains of hills (and it must be remembered that 

 there are at least a dozen running parallel), except in the afore- 

 said bands, on the plains for a long distance, the only rock that 

 is visible is clay slate, inclined at nearly right angles to the 

 horizon, dipping to the west on the western side, and to the east 

 on the eastern side. This slate is extremely fissile, and the 

 stroke is N. 7° W. or five degrees more northerly than the hills. 

 This latter fact is of much importance, as it tends to show that 

 whatever force upheaved the hills, it was different from the one 

 which upheaved the slate to its present highly inclined position. 



On the east side the latter rock is more fissile, often possessed 

 of veins of segregation, composed of either quartz, laterite, car- 

 bonate of lime or specular iron, and containing throughout small 

 cubical crystals of the above named iron ore, or hcematite in such 

 numbers, that where the slate has decomposed and given rise to 

 surface soil, the ground after a shower of rain is literally covered 

 with these crystals, most beautifully exact in form. 



On the west side the slate is entirely schistose, so highly lami- 

 nated as to crumble into scales when rubbed, and so 

 micaceous, that it looks like delicate silk. The strata have 

 become finely waved and exceedingly brittle. Sometimes on 

 both sides the slate passes into an aluminous shale slate, soft 

 and unctuous to the touch, and containing innumerable veins of 

 dolomite and steatite. The latter is found in such quantities 

 in one spot, as to form an article of food for the natives, when 

 pressed by extreme hunger. 



I think there can be little doubt that heat has produced here 

 a chemical change, to cause these appearances both on the east 

 and west sides of the hills. For in a deep crevice or gully on 

 the western side, which descends precipitously to the base of the 

 hill, one sees (at the base), the extraordinary alteration the 

 strata have undergone. The schist has become contorted, so as 



