32 Dr Kelaart's Notes on the Geology of Ceylon. 



successive layers of sienitic gneiss are seen in various stages 

 of decomposition, and these layers retain in some parts, where 

 the decay is not far advanced, the original lines of stratifica- 

 tion. Some of these layers are of pure kaolin, others of a 

 reddish or yellowish clay, some mixed of all three, giving a 

 beautiful variegated surface to these exposed parts of the 

 hills. In half-decomposed portions of some of the hills on 

 the plains of Nuwera Ellia may be seen dark reddish spots, 

 which are formed of decomposed garnets, and in other hills 

 are seen scaly graphite. Adularia and Ceylonite are some- 

 times Pound in the beds of clay. If such, then, be the striking 

 illustration of the decomposition of one form of gneiss in 

 which hornblende and felspar prevail, it is easy to conceive 

 other forms of granitic or gneissic rocks weathering into 

 laterite in other circumstances and other situations. Laterite 

 in any shape is not found in Nuwera Ellia. The stones used 

 here for building are half-decomposed gneiss obtained from 

 lithomargic hills, and it is yet to be ascertained how long 

 these will last. I fear that the decomposed stone is too 

 felspathic to last many years. 



The presence of lignite in some of the laterites of Southern 

 India, and sometimes laterite being found over limestone, 

 would lead us to suppose that laterites are of two periods. 

 The one, and only one perhaps existing in Ceylon, being of 

 the weathering of rocks in situ, and therefore still being 

 formed, and the other a deposit of disintegrated lateritic 

 matter (over more recent formations) derived from previously 

 existing lateritic rocks. The subject, however, requires 

 further investigation : it is involved in greater mystery than 

 many other geological phenomena. Ceylon affords many' 

 opportunities for carrying on observations necessary for its 

 complete solution. The features of the laterite of Southern 

 India which induced Newbold to suppose laterite to be a 

 distinct formation, may also exist in Ceylon, therefore mem- 

 bers of the Asiatic Society will do well to note the nature of 

 the rocks on which the Ceylon laterite lies, and to examine 

 whether any of it contains lignite, or is in the slightest 

 degree fossilliferous. The discovery of fossils alone will not 

 prove that laterite is not decomposed gneiss in situ, for Sir 



