50 JOURNAL, R.A.S. (CEYLON). [VOL. XV. 



the constituents of the rock clearly ; (2) fragments of the 

 upper part of some lofty limestone cliffs most peculiarly 

 weathered — the cliffs looking like coarse sandstone, but 

 the application of acid revealing their true character ; 

 (3) fossil shells, all of the same species, from the base of these 

 cliffs ; (4) specimens of the limestone as it crops up through 

 the beach ; (5) specimens of the raised beach a few feet 

 above sea level — a conglomerate of recent shells and corals ; 

 (6) specimens of shells from the forest soil resting on this 

 raised beach, which is in some parts more than 10 ft. in 

 thickness and full of shells of the same species as are now 

 living on the surface ; (7) specimens of the same soil 

 hardened by the action of the sea and again worn by exposure 

 to the atmosphere ; pottery and recent fresh-water shells 

 sculptured out in the most delicate manner by the gradual 

 wearing away of the hardened earth ; numerous specimens 

 of recent marine shells found in the lower part of the 

 forest soil, and quantities of shells mixed with pottery, 

 showing that a pearl fishery existed here in very ancient 

 times. 



The decomposition of Gneiss and its Products. — Although 

 our rocks are destitute of the interest which the presence 

 of fossils would undoubtedly impart to their study, yet 

 the absence of these organic remains is in a way compen- 

 sated for by the deeply interesting study afforded by that 

 great geological feature of the Island — gneiss, with the 

 various new forms arising from its disintegration. It is no 

 doubt a matter of difficulty for one to comprehend how large 

 mountain masses of hard gneissic rock could change so 

 completely into laterite or moulder away into kaolin and 

 lithomargic clays and finally assume the form of soil. To 

 account for this wonderful transition and mutation under 

 mechanical and chemical influences, we may here inquire 

 into the main constituents of our chief rock, which com- 

 prise, according to " Jamieson's Journal," the most common 

 forms of the following minerals : — • 



