Figure 
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PLATE LV: 
MICROSCOPIC SECTIONS OF RHYOLITES OF THE COUNTY OF ANTRIM. 
Lithoidal Rhyolite, from a column in northern quarry, Tardree Mountain, with minute cavities 
containing tridymite. x 10. 
Perlitic and spherulitic glassy Rhyolite, hollow east of Carnearny. Soda-augite is abundant. A 
spherulite is seen in the upper part of the drawing. x 10. 
Perlitic Rhyolite-glass (Obsidian), from mass 7m s¢tu, north side of Sandy Braes. A slight fluidal 
structure is perceptible. x 14. 
Fluidal, banded, and perlitic glassy Rhyolite (Pitchstone), from a boulder on south side of Sandy 
Braes. x 11. 
Fluidal and banded lithoidal Rhyolite, east end of Sandy Braes. The brecciation of the porphyritic 
erystals of quartz during the flow of the mass is well seen. x 10. 
Fluidal and delicately banded lithoidal Rhyolite, Cloughwater, N. of Ballymena. Porphyritic 
erystals are almost absent from this rock. x 7. 
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