STONE AGES OF CEYLON. 125 
The exact range in time of the extinct and modern species of 
man is at present a little uncertain. Homo sapiens certainly 
existed in the Magdalenian Period, while some now extinct species 
were probably still living. No human remains indisputably older 
than the Chellean Period have yet been discovered. Those which 
have come to light from the older Paleolithie deposits, however, 
all belong to extinct species. ‘The subdivisions of the Paleolithic 
Period are based on discoveries in Europe, and have not yet been 
proved to have a world-wide application. The question of 
Eolithie and Sub-Crag “implements” is still being debated. 
There are high authorities on both sides. 
APPENDIX B, 
Laterite is a product of decomposition of igneous, metamorphic, 
and sometimes sedimentary rocks. Itisthe substance well known 
in Ceylon as “‘ Kabook.” 
The origin of laterite has given rise to considerable discussion ; 
and the term itself has had more than one definition. Geikie 
(Text Book of Geology, London, 1903, Vol. I., p. 169) defines 
it thus :-— \ 
** A cellular, reddish, ferruginous clay, found in some tropical 
countries as the result of the subaerial decomposition of certain 
kinds of rock, as granites, gneiss, diorite, and basalt ; it acquires 
great hardness after being quarried out and dried. The peculiar 
kind of alteration exemplified by this rock and by Bauxite 
(hydrated aluminium oxide) has been termed ‘ laterization.’ ”’ 
A good description of laterite will be found in “A Manual 
of the Geology of India’’ (Medlicott and Blanford), Calcutta, 
MDCCCLXXIX., pp. 348-370. 

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