42 



ROYAL ASIATIC SOCIETY, (CEYLON BRANCH.) 



dolomite, magnetite, quartz, hornblende, tremolite, mica, epidote. 

 Some of these occur, also, as veins in the gneiss. 



In the veins we have the minerals, actinolite, tremolite, 

 jade, talc, muscovite, biotite, epidote, schorl, and many others 

 of minor importance. 



Actinolite is found in the Kotagala district. Good speci- 

 mens of crystalline talc are obtainable from Mahara quarry 

 and neighbourhood. 



The gneiss in some cases almost passes into syenite. 

 Where the felspar is flesh colored, this rock much resembles 

 Peterhead granite. Porphyritic gneiss occurs on the hill 

 ranges not far from Henaratgoda. 



At Balangoda we meet with a crude jasper, and not far 

 from the same locality a large mass of graphic granite in which 

 the quartz is distributed in bands, and when viewed endwise 

 much resembles an inscription. 



When subject to action of water the felspar of the gneiss 

 soon decomposes, and so a large number of decomposed forms 

 are very abundant. As the Island is gradually uprising it is 

 evident that the less elevated portions have been under the 

 influence of water for a longer period, and, consequently, the 

 cuttings through such are less difficult than similar ones in 

 the more elevated portions. Another peculiarity of the gneiss 

 is the occurrence of garnets in large quantity. 



Dolomite beds. As far as I have been able to trace during 

 the time at my disposal, I find that these beds run through the 

 gneiss in a somewhat parallel direction, striking generally N, W. 

 by N. to K, and having various angles of dip. from 10° to 40°. 



I have indicated their position on the map. The first is 

 one which outcrops a few miles this side of Balangoda, and runs 

 N.N.W., occurring again at Hunuwala. 



The second runs through Dolosbage and Maskeliya : pro- 

 bably the bed occurring at Bilhul-oya is continuous with this. 



