254 



JOURNAL, ft.A.S. (CEYLON). 



[Vol. IX. 



not only is graphite lustrous like mica, but specimens occasion- 

 ally occur which can be separated into plates, like lamellar mica, 

 while very dark brown mica, when found associated with plum- 

 bago, simulates to some extent the lamellar forms of the latter 

 mineral. 



Appendix Ho. 11. 



Minerals associated with Plumbago. 



Knowing that Mr. A. Murray, of the Public Works Department, 

 had received a geological training, I referred some specimens of 

 plumbago, quartz, andiron pyrites for his opinion, with the results 

 shown in the following correspondence : — 



Mr. Ferguson to Mr. Murray. 



"I hope you won't think me troublesome, but in my paper on 

 plumbago I wish to make no mistakes. Mr. Williams has kindly 

 sent me some specimens from a mine on the road from the North- 

 western Province to Dambulla, mainly to show how plumbago 

 is associated with quartz. The very best mineral and in largest 

 quantities thus occur. Kindly look at No. 2 in the box sent 

 herewith, and say if I am correct in describing it as crystalline 

 quartz. Mr. Williams wrote of pieces of the quartz looking like 

 Derbyshire spar, and I am sorry he did not send me a specimen 

 separate from the plumbago, but this specimen will enable you 

 to judge if the quartz is normal or any variety worth indicating. 



"No. 1 includes a number of beautiful auriferous-looking bits of 

 iron pyrites, which came in the box from Mr. Williams. You 

 will notice that the golden iridescence shades off occasionally to 

 faint green. Mr. Dixon attributed the green tint to the presence 

 of copper, when reporting on a specimen sent by Mudaliyar 

 Jayetilleke in 1880, when the gold fever was on. Do you agree 

 with Dixon ? Or have we nothing beyond very beautiful iron 

 pyrites ? I enclose a bit of white quartz ending in gold and green 

 pyrites in this letter, which I think of getting set as a brooch. 

 Of course the plumbago people do not delight in iron in any 

 shape, and I am sorry I have not, to send you, a piece of com- 

 pact heavy ironstone, the nucleus of plumbago which Mr. W. 

 A. Fernando told me was unsaleable. I suppose that, apart from 

 particles of iron being in the mineral, the quality of the plumbago 

 was adversely affected by contact with the iron ? In any case, 

 those interested in plumbago love the appearance of veins of 

 white quartz, while, with good reason, they hate iron. 



