BOMAIN 1. SIBEROUS* 



composed of a bluish heavy clay, with an ap- 

 pearance of containing much iron ; he also men- 

 tions a brown kind, found in the coal-mines of 

 Stansby. This rock contains from 20 to 40 of 

 iron, and when rich in that metal is worked as 

 an ore ; being a Gemeiner Thoneisenstein of Wer- 

 ner, which contains about 40 parts of iron in the 

 100. But none are here intended to be included 

 which exceed 20 or 25. It is supposed gene- 

 rally to indicate coal; and if so, that mineral 

 may be expected in Surry. The clay-stone, or 

 argillaceous iron-ore, has commonly a brown or 

 red appearance; while this is grey or black, 

 and probably contains no more iron than basalt. 

 The name iron-stone is commonly used in Surry 

 and other counties ; but it probably is one of 

 the vague whins of the North. It is o.i the 

 gangart of prehnite*'. 



STRUCTURE I. OMPACT. 



Iron-stone, from Surry, Shropshire, &c. 



The same, with prehnite, from Dunbarton, Sec. 



* Mountains of iron-stone exist in the East, if we credit Arab, 

 Rights, vi. 23& of Dr. Scott's edit. 1811. 



