94. PROCEEDINGS OF SOCIETIES. 
has been supposed in some quarters, for it would, in this case, have Te 
duced the ligneous matter to a pulp and destroyed it. The waters of most 
rivers and of the sea contain a very small percentage of silica, which 18 — 
change commences at the surface, so that the internal parts remain largest | 
Neagh is celebrated. The Antrim system of trap-rocks forms part of à 
h 
"igi Whig! h specimens. ‘In the water of this riven - 
as of a similar river, we begs the explanation of the petrifying work P 
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