On Primary Ores of Iron. 363 



.hitherto prevented their fource, or principal mafs, from be- 

 ing explored. 



A vein, which indicated a large field of fupply, was fome 

 years ago traced in the neighbourhood of Muirkirk iron- 

 works, and its courfe followed for feveral miles. T he kidney 

 pieces of this ore are fully as rich and ponderous as thofe of 

 the' Cumberland vein. 



Salisbury Craggs, in the neighbourhood of Edinburgh, 

 afford alfo fome very good fpecimens of an irregular vein, 

 which ftill remains untraced ; apparently the fame ore is 

 found on an eftate belonging to the family of Dundonald, 

 called La Mancha, 10 miles fouth of Edinburgh; the lands 

 of Cranfton alio afford a fimilar ore : the quality of the ore, 

 in both of tbefe places, may be reckoned upon the average 

 to yield 42 per cent, of iron. 



I have feen fome very fine fpecimens of iron-ore picked 

 up in different parts of Fifeihire, where no vein could pofli- 

 bly bedifcovered. 



The fineft Scotch ore I have feen, and which poffeffes 

 mixtures congenial to the exiftence of carbon in the blafl 

 furnace, is found in the Ochil-hills, not above two miles 

 from the Devon iron-works. This ore is foft, loofely 

 filiated, of a reddifh colour, not very ponderous, but pof- 

 fc fli 1 1 ir a fuperior quantity of iron. 



The iron ore of the ifland of Iflay is found regularly 

 firatified, and refemblcs, in point of depofition, the Nor- 

 wegian and Danifh ores. The ilrata are almoft vertical, 

 and are found imbedded in a loofe ochreous earth furround- 

 ed with foil : the fracture of this ore partakes of the nature 

 of the imbedding earth : it abounds with fhining fpecula 

 refembling filex, but which, upon clofer examination, prove 

 to be plates of ilightly magnetic iron-ore. 



Having thus (hortly enumerated fome of various indica- 

 tions of the exiftence of iron-ore in Britain, I fha!l fubjoiu 

 the treatment of two of them widely different in their foffile 

 ifition, their appearance, and their component parts ; 



thefe 



