MINERALOGICAL NOTICES. 51 



analyzed, but I have lately analyzed those from Great Retallack 

 with the following results, viz : 



Silica 41-70 



Peroxide of Iron 35'71 



Protoxide of Iron trace 



Manganese trace 



Alumina 3'20 



Lime 18-52 



Water -25 



99-38 



They are therefore Iron-Lime Garnets. Their hardness is 

 about 6-5, specific gravity 3-496. They are brittle, easily pulver- 

 ised, and small fragments are readily fused to a dark slag before 

 the blow-pipe. The fine powder is slowly soluble — except the 

 silica — in hydrochloric acid. 



The remark has been made that "the Cornish Garnets are 

 associated mostly with greenstone." This is equally true of those 

 from Devon and the new localities are no exceptions. At Great 

 Retallack fine masses of radiated hornblende occur with the 

 garnets and with zinc-blende. I have the pleasure of presenting 

 a fair specimen to the Institution. 



I append brief notices of some other new localities which may 

 be useful for future reference. 



Fluor and Jasper have been found at Great Work Mine in 

 Breage. 



Toad's Eye Tin has been found at Polbreen Mine, St. Agnes. 



Lithia Mica has occurred in large brown plates in the railway 

 cutting at Luxulyan. In the same cutting a fine lode of tin has 

 been exposed. 



Carbonate of Lead has occurred in considerable masses in the 

 railway cutting at Trewithen, in Cubert. 



Cassiterite as pseudomorphous replacements of crystals of 

 Bismuthenite has been brought under my notice by Mr. Rd. 

 Tailing of Lostwithiel. Some of the crystals are merely coated 

 with Cassiterite, others are entirely replaced by a radiating mass 

 of minute crystals. They occur on a mass of cellular quartz 

 apparently from a copper lode. 



On a recent visit to the Gravel Hill part of the Great Perran 



