45® ON THE TOPAZ OF SCOTLAND. 



The Brazilian, and sometimes also the Saxon 

 topaz, are found in alluvial soil # ; and the topaz 

 of Pegu, Ceylon, Hawkesbury River in New Hol- 

 land, and Cape Barren Island in Basses Straits f 9 

 has a similar geognostic situation X* 



Such are the geognostic relations of the topazes 

 of foreign countries. The topaz of Scotland has 

 hitherto been found only in alluvial soil, along 

 with uncommonly large rock-crystals, and middle- 

 sized crystals of precious beryl, and in a tract of 

 country, as far as we know, entirely composed of 

 primitive rocks ; and hence it is highly probable, 

 that its original repository is in primitive country. 

 But in which of the primitive rocks is it probable 



* Topaz has lately been found imbedded, in small cry- 

 stals, in transition rocks. 



f Dr Monro junior presented me with a rolled piece 

 of topaz, said to be from Hawkesbury ri\er ; and Cap- 

 tain Laskey, with a crystal of the same gem from Cape 

 Barren Island, in Basses otraits* 



The topaz of Basses Straits, as my learned friend Mr 

 R. Brown informs me, was first discovered by Mr Hum. 

 phry junior, who was some years ago sent out by Go- 

 vernment to examine the mineralogy of .New Holland 

 and Van Diemen's Island. 



% In the collection of the Museum of Natural History 

 at Paris, there is a large rock crystal, containing red- 

 dish-coloured crystals of topaz from Brazil. 



