SUPPLEMENT. 



a variety in its composition. It is often pretty 

 white, and appears like a quartzy concretion of a 

 porous, or rather a cavernous texture ; and the in- 

 side of the caverns, though small, frequently con- 

 tains a brownish ferruginous soft soil of a snuffy 

 appearance ; and sometimes the insides of these 

 small caverns are finely lined with great numbers 

 of pointed or prismatical crystals, generally ex- 

 ceeding beautiful, and sparkling like diamonds. 

 But all the veinstones, or riders, are not white nor 

 whitish. In many places they are of a brown, or 

 a reddish-brown, and several other colours; but 

 the whitish colour most commonly prevails. 

 Strong wide veins often contain a large rib of this 

 veinstone betwixt the sides, several feet thick ; but 

 in all degrees of thickness, from a few inches up 

 to several feet, 1 have seen strong bold veins carry 

 such a rib or body of this stone as to appear in a 

 ridge above the surface of the ground a great way, 

 the superficies of the native rock being withered, 

 and wasted away from both sides of it."* 



This description clearly applies to quartz : and 

 he afterwards proceeds to mention that the chief 

 spars, found in mineral veins, are the calcareous 

 and cauk-spar, since called barytes. The soft 

 mineral soils found in veins, are a white, or whitish 



* Williams, Min, King. i. 284. 



