272 ON THE TRANSMUTATION OF ROCKS, &c., 



tation is to be attributed to slowly acting molecular and galvanic 

 forces, or to lateral pressure and contact of beds. 



The soft chalk of the Isle of Wight and Ballard Down, near 

 Poole, in Dorsetshire, has thus been converted into a hard lime- 

 stone close to the fault which traverses that range of country, 

 and near to which upheaval has taken place. 



These specimens I collected from Ballard Head in 1835. 

 There is no granite or other igneous rock within many miles of 

 that vicinity. 



One of the most remarkable changes I have ever noticed in 

 the neighbourhood of granite, occurs a little south of Bathurst in 

 this colony. 



At what is called the Great Western Copper Mine, some of 

 the slates are converted into Mica schist and Griesen ; and lime- 

 stones associated with them are changed into white saccharoidal 

 marble, whilst in the slates Tremolite in layers and sulphuret of 

 copper with lead abound. 



So completely is the original structure masked in some of the 

 beds, that I was taken to what was called a limekiln, a con- 

 siderable distance from the marble. A good deal of whitish 

 granular rock had been collected and had been subjected to fire, 

 but in vain, and this whitish granular rock turned out to be 

 Griesen. It was, nevertheless, an altered rock, and I believe 

 altered by granite. Near Bathurst the granite is frequently 

 found decomposed with elvans passing through the decomposed 

 portions. 



In another part of the country, full ninety miles west of 

 Bathurst, the granite of the Sappa Bulgas, or Harvey's Range, 

 has converted ordinary sandstone, very much of the age of our 

 rocks near Sydney, into a vitrified rock such as is here exhibited. 

 The same granite has, further to the west, converted slate into 

 pitchstone and jasper. 



In some countries garnet is a common product of granitic 

 transmutation, and in New Zealand and New Caledonia garnet 

 rock is of common occurrence in the districts where great 

 physical forces have been in operation. The specimen before 

 us is from the north part of the latter island. 



On the eastern flank of the great Maneroo plateau I noticed 



