Vol. 56.] CEYLOX KOCKS AND GKAPHITE. 591 



lies especially in the north), and would separate Ceylon from India 

 more effectually than is now the case. 



Thus endemic species which appeared while Ceylon was farther 

 removed from India than at present, would not have been able to 

 spread to the Peninsula as easily as would now be possible. The 

 elevation may be comparatively recent, and is perhaps still going on. 



Previous to 1 887, remarks on the geology of Ceylon which have 

 been made in books dealing with the island have been of a general 

 character. The articles on the geology in the works by Sir Emerson 

 Tennent [6] and ' An Officer of the late Ceylon Rifles ' [9] are 

 worthy of note. Since then, important contributions to our know- 

 ledge of Ceylon geology have been made by Sandberger [14], 

 Lacroix [17], Walther [18], Melzi [29], and Diersche [30]. No 

 geological survey is in progress in Ceylon, and it is much to be 

 hoped that the Government will soon realize the importance of 

 instituting one. 



My thanks are due to Major-General F. T. Hobson, E.G.S., who 

 kindly accompanied me to the Mahara Convict-quarry ; to Mr. Edgar 

 Eerdinand of Kurunegala, who showed me the Ragedara graphite- 

 mines ; also to Mr. Peter D'Abrew of Colombo, to Mr. Modder of 

 Kurunegala, to Messrs. Casa Lebbe & B. Weerasiri of Kandy, to 

 Mr. Kellow of Hakgala, to Mr. B. Seneviratne of Galle, to 

 Mr. Hector van Cuylenberg of Colombo, to Messrs. A. A. C. W. 

 Jayasekara & L. S. Amarasekara, and to Mr. Bell, Archaeological 

 Commissioner. 



In England my thanks are especially due to Prof. Bonney, who 

 has most kindly superintended the writing of this paper, which 

 could not have been prepared without his assistance, and who 

 allows me to say that the penological determinations 1 made in it 

 have his approval ; to Mr. Teall, who has also very kindly given 

 assistance and advice ; to Mr. R. Graham, who kindly measured 

 the crystals ; and to Mr. S. Hastings, of Middlesex Hospital, who 

 analysed a pyroxene. 



II. The Recent Deposits. 



The greater part of the coast is fringed by coralline raised 

 beach, and in the north a large area consists of bedded sea-sand 

 and coralline limestone. In going by rail from Colombo to Galle, 

 numerous diggings in the rubbly coral-limestone are seen ; it 

 is burnt for lime which is used in building or as a constituent of a 

 chewing-paste. In some places considerable areas of pure sandy 

 deposits are found, as in the Cinnamon Gardens, Colombo, where 

 the soil is said to contain 98 per cent, of silica. 



1 [It may be mentioned here that details of pleochroisrn, extinction-angle, etc. 

 are not given in the descriptions when they are quite normal, but that the 

 determinations are based on the careful use of the usual methods, including 

 examination in convergent polarized light. The figures given in parentheses after 

 the word ' plagioclase ' in many cases serve to indicate the highest measured 

 extinction-angle from albite-lamellse, in each instance. — July 2nd, 1900.] 



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