II. A Description of the Red Oxyd of Copper ^ the production of 

 Cornwall^ and of the Varieties in the form of its Crystal, 

 ivith Observations on the Lodes ivhich principally produced it ; 

 and on the Crystallization of the arseniated Iron. 

 By William Phillips, Member of the Geological Society. 



1 HE Mine called Huel Gorland, in the parish of Gwennap and 

 county of Cornwall, is in a hill whereon is situated the town of St. 

 Day, to which it is immediately contiguous eastward. In this mine 

 there are seven lodes ; one of tin, the others of copper ; but as only 

 three of the latter have produced the red oxyd of copper, it will not be 

 important further to notice the others. These three lodes are known 

 by the names of the North Lode, the Great Gossan Lode, and the 

 Muttrell Lode. The latter, is that noticed by the Count de Bournon, 

 as having produced the arseniate of copper, in a paper published in the 

 Transactions of the Royal Society, in which he has so ably and scien- 

 tifically described that mineral. 



In the North Lode which runs eighty fathoms north of the Great 

 Gossan Lode, the red oxyd of copper was occasionally found with 

 fluate of lime ; though, compared with the quantities produced by 

 the other two lodes, very sparingly. 



The Great Gossan Lode averages about four feet In width ; the 

 Muttrell Lode about three feet. The former runs eight degrees from 

 the north of the west, meeting the latter, which runs four degrees fron^ 



