\Q2 LA TOUCHE : GEOLOGY OF NORTHERN SHAN STATES. 



both areas ; and there is certainly a greater variety of trilobites in 

 Buirna, as well as a much greater profusion of individuals. What- 

 ever may have been the nature of the barrier, then, that separated 

 the Burmese and Himalayan life-provinces in Ordovician times, it 

 seems to have remained unsurmountable by marine organisms until 

 the close of the Silurian epoch, 



