256 
THE SILURIAN VOLCANOES 
BOOK JV 
thick layer over the bottom. But the life that teemed in the sea, thouch 
temporarily destroyed or driven out, soon returned. Corals, crinoids and 
shells found their way back again, and fine sediment carried their remains 
with It and filled up the crevices. The ejected volcanic blocks are thus 
enclosed in a highly fossiliferous matrix. 
A succession of lava-streams, of which the strongiy-nodular sheet of 
Clogher Head is the thickest and most conspicuous, mark the culmination 
of the volcanic energy, and show how at this late part of the Silurian period 
felsites that reproduce some of the most striking peculiarities of earlier time 
were once more poured out at the surface. A few more discharges of tuff 
and the outflow of a greenish flinty felsite brought this series of eruptions 
to an end, and closed in Britain the long and varied record of older Palteozoic 
volcanic activity.’ 
As tins sheet is passings tliroiigli tlie press, tlie interesting pajier by Messrs. S. H. Reynolds 
Ti Kildare Inlier” has appeared (Quart. Jnurn. Grot. Soc. vol.^Ki. p. 
o /}. lese authors give petrographieal details regarding tlie lavas, which they show to" he 
andesites and basalts of Bala age, associated with highly fossiliferous tufi's. 
