LIST OF ILLUSTRATIONS 
fig. 
1. Vesicular structure, Lava from Ascension Island, slightly less than natural size 
2. Elongation and branching of steam-vesicles in a lava, Kilninian, Isle of Mull, a little less 
than natural size 
3. Microlites of the Pitchstoiie of Arran (magnified 70 diameters) . . . • 
4. PeiTitic structure in Felsitic Glass, Isle of Mull (magnified) . . . • 
0. Spherulitic structure (magnified) 
0. Micropegmatitic or Granophyric structure in Granophyre, Mull (magnified) 
7. Ophitic structure in Dolerite, Gortaeloghan, Co. Derry (magnified) 
8. Variolitic or orbicular structure, Napoleonite, Corsica (nat. size) 
9. Flow-structure in Rhyolite, Antrim, slightly reduced . . ■ ■ • 
10. Lumpy, irregular traohytic lava-streams (Carboniferous), East Linton, Haddingtonsliire 
11. View at the entrance of the Svinofjord, Eiroe Islands, illustrating the terraced forms 
assumed by basic lavas 
12. Sack-like or pillow-form structure of basic lavas (Lower Silurian), Bennan Head, 
Ballantrae, Ayrshire 
13. Alternations of coanser and finer Tull' ..•••' 
14. Alternations of Tuff with nou-volcanic sediment . . . • • 
15. Ejected block of basalt which has fallen among Carboniferous shales and limestones 
shore, Pettycur, Fife 
Ifi. Effects of denudation on a Vesuviau cone . • • • * 
17. Section to illustrate the structure of the Plateau type . . • • 
18. Diagram illustrating the structure and denudation of Puys 
19. Section illustrating submarine eruptions ; alternations of lavas and tuffs with lime 
stones and shales full of marine organisms . . ■ • ■ 
20. Diagram illustrating volcanic eruptions on a river-plain . • • • 
21. Diagram illustrating volcanic eruptions on a land-surface 
22. Ground-plans of some volcanic vents from the Carboniferous districts of Scotland 
23. View of an old volcanic “Neck” (The Knock, Largs, Ayrshire, a vent of Lower Car 
boniferoiis age) 
24. Section of neck of agglomerate, rising through sandstones and shales 
25. Neck filled with stratified tuff 
26. Section of neck of agglomerate with plug of lava . • ■ ■ 
27. Section of agglomerate neck with dykes and veins • • ■ • 
28. Section of neck filled with massive rock ...••• 
29. Successive shiftiiigs of vents giving rise to double or triple cones 
30. Section to show the connection of a neck with a cone and surrounding bedded tuffs 
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