176 HOLLAND: SIVAMALAI SERIES. 



separate occurrence presents a peculiarity of its own. The whole 

 complex — elaeolite-syenite in all its varieties, augite-syenite 

 (laurvikite), corundiferous felspar-rock (corundum-syenite), and pro- 

 bably acid pegmatites with beryl — are regarded as the products of 

 the differentiation of highly alkaline and aluminous magma, intruded 

 into the crystalline schists at a period unknown, but in all probability 

 geologically very ancient, 



( 8 ) 



