160 Proceedings of the Royal Society of Edinburgh. [Sess. 
Groups. 
Rhyolite, 2, 3, 3, 3, 3, 4, 4, 5, 6, 6, 6, 6, 8, 8, 
8, 9, 9, 10, 10. 
gneiss, 3. 
obsidian, 5, 7, 9. 
Rhyolitic obsidian, 19. 
rock (tuffac.), 7, 11. 
Saxonite, 58. 
Schonkinite, 42, 61. 
Soda eurite, 6. 
felsite, 3, 5. 
rhyolite, 5. 
syenite, 29. 
porphyry, 23. 
trachyte, 27. 
Sodalite syenite, 32. 
Sodal. aug. syenite, 47. 
Solosbergite, 23, 24, 28. 
Spilite, 53. 
Syenite, 14, 14, 18, 24, 26, 28, 38. 
lampophyre, 42. 
pegmatite, 82. 
porphyry, 19, 22, 23, 24, 26. 
trachyte, 27. 
Tachylite, 39. 
Tachylitic rock, 20. 
Tephrite, 39, 39. 
Teschenite, 35, 39, 56. 
Groups. 
Theralite, 46, 55. 
Tinguaite, 15, 23, 23, 30, 31, 31, 32, 45. 
Tonalite, 18. 
aplite, 5. 
gneiss, 22, 33. 
Tourmaline granite, 12. 
Trachydolerite, 30, 31, 39. 
Trachyte, 3, 4, 14, 14, 14, 15, 15, 15, 16, 18, 
19, 20, 21, 23, 24, 27, 28, 28, 28, 28, 
30, 30, 30, 33, 48. 
andesite, 29. 
pumice, 15, 15. 
Trachytic rock, 23. 
Trap, 35, 53. 
(glassy) 53. 
Tridymite trachyte, 9. 
Umtekite, 27, 27. 
Uralite porphyry, 51. 
Vitreous basalt, 43. 
Volcanic bomb, 41, 
breccia, 26. 
rock, 42, 42. 
sand, 41. 
Websterite, 50. 
Wehrlite, 50. 
Wyomingite, 26. 
{Issued separately February 1, 1908.) 
