176 Metamorphic Rocks in South Australia. 



There is one rock which is so rich in magnesia as to give rise to 

 great beds of steatite, and another is so aluminous as to aftect 

 the taste of water in the neighbourhood, which water gives large 

 quantities of alumina on analysis. In both the rocks the stratifica- 

 tion is perfect, and their composition gives one an idea of the sin- 

 gular state of the ocean from which they were deposited. Sulphur is 

 also present. I exposed a large quantity of the powdered rock, 

 to heat in a retort, and the quantity of sulphur that sublimed 

 was quite surprising. I could detect no sulphates. At a 

 place, east of the hills, so often alluded to, there is a vein of iron 

 ore, and the strata on each side are variegated with most singu- 

 lar colours. I have one specimen where the rock is changed to 

 a most beautiful blue, of the finest hue that could be imagined, 

 so distinct was the colour that I actually analysed a portion to 

 detect copper or cobalt before I became aware that this was owing 

 merely to the influence of heat. 



In conclusion, it may be said to those who are fond of 

 regarding South Australia as a country, the whole of which has 

 been recently raised from the sea, that these rocks at least, and 

 a great portion of the country immediately around, were certainly 

 dry land at a time when the sea rolled over the spot where 

 Adelaide now stands ; and if, as I believe it may be proved, the 

 south coast of South Australia was under water at a recent 

 period, tracts of country such as Clare, and the Mount Lofty 

 ranges formed an Island Archipelago. The sea beat overland 

 where the busy hands of men have now raised a city,, using for 

 that purpose the very spoils which the ocean left behind, but 

 while it did so, it spared a spot where fire had exerted its 

 underground ravages ages before, leaving rocks and stones to tell 

 to man, the magnitude and power of the earth's Great Framer. 



